Absolutely agree with those factors as well: it's such a perfect storm that I doubt it's possible to pinpoint one major contributor.2 large factors which might be the biggest ones:
D&D is inclusive now.
People want to be social away from screens. This is a huge reason why boardgames have exploded in popularity. D&D is like that but more imaginative and cooperative than most board games (also has less structure which enables more time to be social)
Just about the only thing that hasn't broken in WotC favor for 5E is major multimedia breakout with a hit video game, TV show, or movie: if they can manage that with even modest success, then the game will likely benefit even more than we are seeing now.