"Why" is a really hard question for anything in history. I'll put forward a few theories.

One is that it was overshadowed by geopolitics at the time. The Spanish Flu happened immediately at the end of and after WWI, and for many reasons WWI was seen as the more important and more noteworthy event in the context of the times. Additionally, WWI did not really have a clean, sharp ending, although often it is taught that way in simplified histories. In Russia the ending of WWI overlapped with the revolution, and bled into the 5+ year long civil war (which involved participation by numerous external forces. You also have the dissolution and eventual partitioning of the Ottoman empire and the "Arab revolt" et al taking place during and immediately after WWI which changed the landscape of Western Asia and the middle east. Then you have China, which saw the end of the Qing dynasty just prior to WWI melding into a period of instability, chaos, and ultimately civil war that would last through the 1940s. Then there's the "United Kingdom", which saw an uprising in Ireland during WWI and then a full on war of independence fought through the early 1920s culminating in the creation of the independent Irish Republic. And I haven't even mentioned all of the crazy shenanigans going on in the rest of Europe during that period. The whole mess with Germany, the dissolution of the Empire of Austria-Hungary, etc. In short, there was a lot going on at the time and looking back on the events from the perspective of, say, the 1930s, '40s, '50s, etc. the events that seemed to be the most important and most impactful seemed to be geopolitical in nature and the Spanish Flu just ended up as a side note.

Another major point worth considering is that deadly worldwide pandemics are much rarer and more notable today than they used to be. The 1918 H1N1 flu was not the only pandemic during the 20th century. The early 1900s was a time when a wide variety of diseases were circulating, some with notable outbreaks, some even spreading as pandemics. Typhoid, polio, smallpox, yellow fever, scarlet fever, TB, malaria, cholera, even plague, all of these were common threats to health across the globe and even within the industrialized nations. It was not until the mid to late 20th century that improvements in public health and sanitation combined with dedicated efforts at mass vaccination and disease eradication would dramatically lower the overall burden of infectious disease in the developed world to the low levels we see today. In the context of the early 20th century the flu pandemic was notable quantitatively but less so qualitatively. And even in terms of raw numbers the peak death rate due to the flu in the US (for example) only exceeded the previous overall death rate due to all infectious diseases from 1900 by only about 25% or so. So in a lot of ways the pandemic was more of a major bump along the path towards reduced mortality from infectious disease that had been playing out for decades. At the time infectious diseases were already the major leading causes of death throughout the world, so in terms of raw character the flu pandemic was not unusual.

Record keeping and epidemiology was much poorer a century ago, so people had a very incomplete picture on the global impact of the 1918 flu at the time. It was not until decades later that the full scale of how many died around the world was accurately estimated and truly appreciated.

Every culture would have a unique experience and impact to the Spanish Flu, it was very much not a blip to the Inuit of Labrador for example.

When the Spanish flu arrived in the Dominion of Newfoundland in September 1918 I would guess its impact was unique. St. John's saw a number of cases and put a call out for nurses to help the increase of patients that were suffering from the flu. I'm not sure how the remote nature of settlements impacted the flu's transmission and lethality. I would think though that when the flu arrived in communities they would be hit hard since there was virtually no health care. In total Newfoundland saw around 220 deaths, of a population of around 240,000-250,000 (it was 242,000 in 1914 and the majority would have been on the island and it might not have included the indigenous people of Labrador.) The situation was much worse in Labrador.

Cases were brought by government mail and supply boats and where around 1% of the Newfoundland population died about 10% of Labrador's did. In Hebron 86 of 100 people died, Okak lost 204 of 263 residents, 40 of 45 died at Sillutalik, and 13 of 18 people died at Orlik to name a few. The death of hundreds in small communities would always have a severe impact, economically Okak had been one of the most prosperous communities. After the flu all adult males had died and the survivors left, it ceased to exist. Survivors had to deal with more than leaving their homes, some of which were the only places they had ever known. Since the flu had arrived in late October and had spread from then northern communities were unable to burry their dead. In Okak the dead outnumbered the living and as sled dogs began to get hungry they started eating remains, in other communities bodies were stored in now empty dwellings. After the flu left over 30% of the Inuit population had died, communities which were once prosperous were gone. This left a massive scar on not just individuals but an entire population.

So why was the Spanish flu not well represented in culture, in this example Newfoundland had just come out of the Great War where over 1400 young men had been killed and many more injured. Following this the Dominion would be thrown into economic turmoil from the war debt, cost of the railway, and crash of not just banks but cod fish. History would generally focus on these events but also would focus on the larger and whiter population of the island. The impacted populations of Labrador though would see lasting scars and it would have a great impact on Inuit culture.