Something I have noticed in what I call "history fandom" circles is that there is a tendency to take periods as prescriptive (telling you what's important) rather than descriptive (describing something that's happening). Historians don't typically come up with names for periods that everyone must use based on some sort of analysis of one era-defining person or event being the most pivotal thing: they look at what they are studying and label it accordingly, to be useful to them. This is why we have the concept of "the long eighteenth century" - there are a lot of historians studying various late-eighteenth-century topics that continue on until about 1815, and it's useful for them to have a label describing that. They did not come up with the term to force the general public to consider the eighteenth century longer than other centuries in all ways. Likewise, "Victorian" is not a common term in nineteenth-century studies because historians think there is an inherent value in treating 1837-1901 as a distinct block of time, but because they study something within it, and it is useful to them to distinguish the era.

When it comes to Tudor vs. Elizabethan, the distinction lies in the fact that historians are typically studying either Elizabeth's reign or Henry's. "Henrician" is used in academia, but it has no foothold in popular culture - "Tudor" tends to mean specifically his rule, although you will also find it used to more broadly cover the reigns of Henry VII, Edward VI, and Mary I. Historians who are studying any of them specifically, though, are likely to not refer to the period as "Tudor" but to be specific about the ruler whose reign is most relevant, just like "Elizabethan" - but there has historically been much less study of these others.

The major reason for this is that Elizabeth's reign was considered a "golden age" for England and so was much more attractive. It's seen as a flowering of literature - Shakespeare and Spenser, for instance, are seen as not only very good writers but as writers whose goodness is intertwined with English identity. There's also the rise of the British Empire, and a perception of military victories occurring under her, although the latter is largely due to the destruction of the Spanish Armada (which was itself partially due to English naval skill and partially to chance); there were many defeats and stalemates during her reign that are simply forgotten about in reconstructing the era as a time of peace and/or victory. She also legitimately had a longer reign than her half-siblings - 45 years, in comparison to 5 (Mary) and 6 (Edward, all under a regency) - which gave more room for things to study. And perhaps most importantly, she solidified the dominance of the Church of England, which she was also perceived as being an adherent to in a more disinterested and devoted way than her father - to later Anglicans, her reinstallation of the "true church" after Mary's return to Catholicism was tremendously important and put her on the right side of history. Elizabeth was also very good at PR, and had herself depicted in many glorious portraits as a beautiful, stately, and above all else gorgeously-dressed queen to be reckoned with.