Not solely of course, but 5e did arrive in a good period to go more mainstream.
Stranger Things, Community, Game of Thrones, super hero movies and comics considered cooler and more mainstream, some celebrities saying they play and the word getting out through social media, streaming, etc.
I'm not going to try to estimate how much that effected success or not but think it had some effect.
Many, many things have contributed to 5E's success. Just like many, many things contributed to 4E being replaced. I don't think anybody has much of a clue of what factors figured into either one.
All I know is that while Stranger Things may have lead to an increase in web searches, but if you look at sales history 5E was already on an upward trend that didn't change much. All the things that people credit 5E's success with (other than the actual rules of the game of course which saw double digit growth before Stranger Things or CR) started years ago and don't explain the continued growth.