It isn't their fault, but it did happen.

That's... part of it, but part of it is just ease of use. In growing up, I had to figure out issues with my computer,and getting games etc working took some work to do. I build a gaming PC for my nephew(under 10, but games a lot mobile and with consoles) and he played a few games on it, but then my sister (a gamer herself) said he couldn't really get used to keyboard over controller (at which point I reminded her she could just get him a PC controller or use one of the console ones that also work on PC).

He just seems to prefer to use things that are already intuitive, and since my childhood things have gotten much better in that regard for consoles and mobile stuff. You can definitely do it on PC as well, but it often means more accessories, sometimes figuring out issues . I got another sister of mine a controller for pc and it took a bit of effort getting it properly synced for the game she wanted to play. It would show up properly in the OS, but then the game he issues, so we had to switch through modes and such, and sometimes even though one mode may work an update or something may break it.

I like using controllers for some games, and WASD for others, but even though IT is my job and I'm good at fixing things, some games have weird issues with some controllers, especially if they have mode options. All that extra fixing and finding the right settings is just frustrating for some, and with easy to use alternatives they may not bother to learn. I had no choice, just SNES and pc while growing up.

No one taught me how to use a computer, I figured it out as I went. I had to tell my 25 year old brother that theres more than one USB port on the back of his computer because he only saw the one in the front and asked me where he plugs in the keyboard and mouse.

Part of the issue for a lot of the older and younger crowd is "Well, it's not immediately obvious, so therefore its impossible and now I'm mad at you for it."