Most folks never did need the books to learn to play. You’ve always been able to learn D&D by somebody (usually their DM) explaining it. But many people end up buying books and things once they’re engaged.
Like any hobby, people spend money on it when they want to. Those solid modules and supplements you mention would be a bit part of that, but also how people feel about the company they’d be supporting matters a lot (this is the so-called “reflective reaction” Don Norman writes about in his book Emotional Design) .
Most folks never did need the books to learn to play. You’ve always been able to learn D&D by somebody (usually their DM) explaining it. But many people end up buying books and things once they’re engaged.
Like any hobby, people spend money on it when they want to. Those solid modules and supplements you mention would be a bit part of that, but also how people feel about the company they’d be supporting matters a lot (this is the so-called “reflective reaction” Don Norman writes about in his book Emotional Design) .