This is a good example of why this discussion can get complicated. "TTRPGs" can encompass a lot of side hobbies. Collecting dice can become an expensive hobby but it is not required to have expensive or even multiple sets of dice to play. If you stick with just what you need to play, an RPG is quite inexpensive as hobbies go. But for those who get really into TTRPGs, many expand the hobby into many side hobbies. A lot of the expenses I see discussed seem to be more "collector" hobbies. If you buy games that you don't play, you are just collecting them. Just about any TTRPG that you buy and actually play for a few sessions is quite cheap.
As many RPGs, esp. D&D move to more of an on-line and play-by-VTT subscription model, then it becomes more akin to streaming services. I think that changes the calculus.
You can get a TTRPG PDF for free or very cheap and, if it is a popular system, there will be lots of free fan-content online. But I would guess this isn't what most players are doing. I'm not even sure that most players are still playing using only physical books and pencil and paper.
I would be very interested in seeing a poll focused on just D&D that asks how much folks are paying for D&D Beyond and/or VTT subscriptions. Then compare that moving streaming service and video game spend. Also ask whether DMs are fronting all the subscription costs or if their group cost shares.