Coincidentally there's been a Guardian article published today that may be of interest to you (here), but despite the title 'the undying allure of ancient Egypt', it proves very little about that 'allure' and instead ends up as self-promotion for the author's upcoming release.

Despite that, there's a lot to be said for Egyptology before and during the discovery of Tutankhamun. The study of Egypt, and the wider ancient Near East thrived from the 18th century onwards. Significant expeditions/investigations of the 18th and 19th century were those of Carsten Niebuhr (1761-67), Karl Lepsius (1842), and throughout the life of Flinders Petrie, who published major works from the 1880s up to Carter's time. In the earliest days of these nascent fields of archaeology, there were a number of salient aims - one was searching for 'truth' behind Biblical texts - for example interest in the Sumerian city of Ur as the birthplace of Abraham. The other was the decipherment of ancient languages, which had an international, competitive slant. If you're interested in funding, at least in their earliest iterations these expeditions were state-sponsored affairs, with decipherment firmly rooted in international academic competition.

The field of Egyptology itself gained a huge boost when hieroglyphics were deciphered by French philologist Champollion in 1822, at the peak of early French scholarly Egyptomania. In respect to the chronology of your question, this is still 100 years before the major discoveries of Carter. So what made his discoveries so noteworthy?

Carter's expedition being inherently noteworthy is not a matter of debate. He uncovered an intact tomb from Egypt's golden age, the New Kingdom, which was unprecedented and has still never been outdone in terms of scale. However, it was a cruel coincidence that the king he discovered happened to be Tutankhamun, one of the least remarkable kings of the 18th dynasty, a dynasty which included greats such as Hatshepsut, Thutmosis III, Amenhotep III, and the notorious Akhenaten. The single most remarkable thing about 'Tut's' tomb was that it was intact. The fact that such wealth had never been seen before wasn't a reflection on the excessive grandeur of Tutankhamun, rather an accident of discovery. Modern Egyptomania owes a lot of its prestige to this accident. But there's another factor to consider.

Carter's expedition was a high profile affair from the get go. Carter had the support of one of Egyptology's 19th century heavyweights, Gaston Maspero, who surveyed many of Egypt's most famous sites, as well as being deeply involved with Egyptian museums and early mass tourism in the region. Egyptological study also had to be funded - that was where Lord Carnarvon came in as Carter's sponsor. And naturally, The Times were present at the opening of the tomb. In order for public excitement about ancient Egypt to reach the fever pitch it did, it had to have a lot of clout already behind it - academic, private, and media. And it was this machine that carried modern Egyptomania forward - after the Tutankhamun discovery Carter toured the UK and US giving lectures about his discoveries and ancient Egypt in general.

The TL;DR of the matter is that there had been an academic enthusiasm for the ancient Near East for over 150 years. But Carter's discoveries were a product of a sustained private interest in the field that ensured greater funding and public excitement for much of the early 20th century.

BONUS: Paul-Émile Botta, a French archaeologist discovered/recorded a remarkable number of Assyrian and Babylonian artefacts in the mid-19th century. They tried to ship 235 cases of statues, reliefs, and other movable objects back to Paris - beginning by heading downstream from Nineveh to Basra on the river Tigris. A number of the barges and rafts sunk, sending thousands of years of Assyrian history to the bottom of the river. Its been said that if his colleagues were successful in bringing the majority of these artefacts back, we'd have seen Assyriomania spread across Europe instead of Egyptomania.

While King Tut's discovery was a watershed moment for the Egyptological community, it was certainly not the beginning. Most of the real 'boom' in Egyptology occured at the turn of the century, with archaeologists such as Flinders Petrie and John Garstang leading the way. (I'm going to link some information/refs in a separate comment below).

Petrie was one of the real pioneers of Egyptology and archaeology - his methods (while primitive today) were innovative for the time, due to his system of labelling and also the relatively new use of photography, allowed for proper documentation of finds for the first time. However, while archaeologists such as Petrie held a true interest in Egyptology, the main source of funding was the public - as a result, Egyptology at this time was more of a rich man's sport. It was considered a status symbol to be able to go over to Egypt and essentially loot archaeological goods. Indeed, 'mummy unwrapping' parties were highly popular among the elite during this time - to be able to say you could afford to have a mummy brought over specifically for you from Egypt was an ultimate symbol of wealth and status. I hate to say it but there is no doubt an element of race within this, whether subconsciously or not; Egypt was a British colony at this time, and as a result, its culture was fair game so to speak - the British could essentially steal the history and artefacts of Egypt with very little (if no) consequences.

It can be argued that before 1922, Egyptology was more of a pursuit or pastime for the rich. While archaeologists themselves were passionate and knowledgeable about the science and the history, the subject seems to have been more of a trend or fad due to their discoveries. It can be said that Carter's discovery allowed Egyptology to be rediscovered itself - to be taken seriously and seen as a true science. The sheer volume and value of the finds in the tomb made people sit up and pay attention - it was front page news. Suddenly people were even more interested in Egypt, no matter what their status or wealth. It no doubt inspired many more people to pursue the study, although some undoubtedly for their own fame or glory. The discovery of King Tut awakened an excitement in the general public, and proved to archaeologists that their work could be popular as well as fruitful. It allowed for a vast amount of funding, as well as increased fervour for Egyptology, but that does not mean it was not already present.

After the war, and in the early twenties, helped along by Carter's discovery, more and more archaeological institutes began to be founded - in Chicago, the Oriental Institute gained funding and fame. In the UK, Liverpool hosted and archaeological institute for Egypt and the Near East. The Museum of Fine Arts in Boston also gained more of an Egyptological collection. Indeed there is even a term for this newfound excitement - Egyptomania. I've linked a couple of articles below about it but it's essentially what I've already covered; the fervour and desperation to have a piece of Egyptian culture and to be a part of the discoveries being unearthed. This is seen with Napoleon in 1809, when volumes of his commissioned Description de l'Egypte started to be published following his 1798 expedition there. The boom in Egyptomania that followed its publication is mightily similar to that which accompanied the 1922 discovery - it is only natural that large and exciting discoveries breed more excitement.

So to answer your question, yes and no. To academics of course this was a huge deal - to discover something that big is not only a very rare occurrence but also a godsend as it allowed for funding and more interest. It was a watershed moment in that it brought huge public interest and therefore money to a field which (let's face it) drinks up the stuff like the deserts they dug in. And yet while the discovery was massive, it also wasn't the first - Napoleon and Petrie had also paved the way, and therefore to Egyptologists, this could be considered just another step in their journey to discover more about such a complex culture and nation.

I'm basing my answer on what I know from my limited museum work, but I hope it's a good start!