I don't think I would put the success of 5E down purely to luck, it was a very intentionally designed product meant to reinvigorate the brand, which was losing out to Pathfinder at the time, following the failures of 4th edition. 5E was a bold step towards very simple, very broad design. Gone are the days of Tomes of Vile Darkness and obscure 3.x splatbooks, the era of 5E was meant to sell a small number of products to every single player, as opposed to the marketing philosophy of 3.x, which was to sell a huge variety of products to cover the needs and desires of every conceivable player.
There's a very good reason why all the 5E splatbooks are extremely basic stuff that for the most part is just "more monster manual" or "more player's handbook". Those types of books appeal to every single 5E player.