Here's a little quote from a website that actually has numbers:
There are currently an estimated 13.7 million active tabletop D&D players worldwide. Since the inception of D&D in 1974, that number has continued to grow. And with D&D becoming more mainstream, projections are that the number of D&D players will continue to rise.
Core D&D rules difficulty setting is a requirement at this point, with so many liberties being taken that actually make the game worse, not better.
