I agree that Microsoft is not good, and wish that Linux were a good alternative for most people. I assume your mom does basic web browsing, and if that's all someone needs to do it will work great. Just out of curoousity I Googled how to install League of Legends on Linux and came up with this guide from 2017:
Now imagine I wanted to install something that wasn't nearly as popular, and you will see the problem I see. Like I said, basic web browsing works fine but most people don't just want to do that.
How about iTunes? I just Googled and found this:
"If the initial installation doesn't work properly, try an earlier version of iTunes. The only downside of this, of course, is that earlier versions may not have the latest features or support syncing with the latest iOS devices."
It's always something tricky on Linux. Say what you will, but it doesn't have billions of dollars to make it seamless to the end user like Windows does. It's gotten way better than the first time I used it way back in 1995 where I had to spend hours just to install a CD-ROM drive, but if you do anything more than browsing the web, it's not yet where it needs to be for most users in terms of ease of use.