But a lot of 5E's success can be credited a lot more to being in a perfect storm situation. Geek culture stuff has gotten trendy and cooler than ever before and really took rise in the 2010s, you have McCree and Jaina Proudmoore's VAs streaming themselves playing D&D along with other "e-celebs" which is free promotion, even if D&D was stuck in that immensely shit 4E it would likely blow up in popularity as well. 5E's popularity has less to do with it being a genuinely great system and more that it happened to exist in the same neighborhood this tornado of nerd exaltation took place. Personally speaking, 5E isn't bad but let's face it: next to 4E just about anything would be better.
And I will even go further and claim this: I bet most people that purchase 5E stuff don't even play it or homebrew the shit out of things so hard it may as well be something else entirely. As I mentioned, nerd culture is trendy and hip, have some D&D books on your shelf and you look like you're "about that life."
5e is succesful because is less focussed around rules.
The focus of 5e is rpg. This is why critical role worked: they are actors and the 5e allow them to do their funny voice for 4 hours so people can watch them and having fun.
so a new player don’t need to learn a single rule he just need to think about a character and the DM can do the rest.
combat is also faster ( and a full round can still take 15-20 minutes when you have many players)
so the success come to be easy to play and easy to DM.