Consider the continuing popularity of high end / AAA video games, which can cost anywhere from 60 euro / dollars to 70 euro / dollars and the consoles to run them on, along with smaller games. Though the video game industry has changed a lot of the years, there are still a number of games where those over 13 would be a large demographic consideration you have to take account one - one generally assumed to have some way to purchase said games.
I would generally assume that the disposable income of people aged over 13 years would not be the biggest barrier to purchasing TTRPG books for that demographic - especially since material for a TTRPG can often be much less than 60 euro, and you can get potential dozens upon dozens of hours of playtime from one book purchase; this may not hold true for a number of AAA video games, depending on a player's individual interests (if you buy Call of Duty just for the campaign - which is a sizable part of the CoD community - and you buy at lunch - then depending on the game, you may be paying 10 euro for every hour you spend enjoying the game).
I would generally assume that the disposable income of people aged over 13 years would not be the biggest barrier to purchasing TTRPG books for that demographic - especially since material for a TTRPG can often be much less than 60 euro, and you can get potential dozens upon dozens of hours of playtime from one book purchase; this may not hold true for a number of AAA video games, depending on a player's individual interests (if you buy Call of Duty just for the campaign - which is a sizable part of the CoD community - and you buy at lunch - then depending on the game, you may be paying 10 euro for every hour you spend enjoying the game).