Ruin Explorer
Legend
I think that 5E's popularity is a combination of multiple factors, not merely diversity in art and rules.
The simplified and streamlined ruleset (too simplistic for my tastes, sometimes) was probably one of the greatest selling points.
I think the fact that the generation that grew up playing 2E is now in charge of the media, and that streaming has made a lot of people who were maybe "RPG curious" far less afraid of the concept, and even excited by it, thanks to things like Critical Role, is pretty significant, more significant than anything specific about 5E. Though I will say 5E was the right game at the right time - it's more accessible and immediate than 4E, for example, easier to get into, which really helps with new players. That had to be the case for it to take off like it did.
Random aside - a teacher I know told me he tried to be "down with the kids" by talking about Fortnite recently, only to have teenage eyes rolled at him and be told "Fortnite is dead" or words to that effect, and when he asked what they were playing now instead, was told it was this thing he wouldn't understand - Dungeons and Dragons (and they definitely meant the pen and paper version).