You haven't been paying attention. Literally the best selling item on Steam for nearly a year and a half was a Linux Gaming PC.

Linux is far more flexible than Windows. The nature of open source is what enables such flexibility. The only reason Linux hasn't been adopted by many is simply because of the chicken and egg issue.

Microsoft and Apple had made a monopoly on the market for desktop computers, And since the desktop market share was so low for linux, few devs developed desktop software for Linux. Which then in turn kept Linux from gaining marketshare.

But the times are changing. Wine, Proton, Lutris and Multi-Platform web app tools have lead to a world where devs can simply just mindlessly go "oh yeah I guess we can enable linux builds/proton supported builds." and just forget about it.

For example, lets say it was 2006 and Discord was just released in that time period. Instead of being a web app, they built a client that communicated using an API for Discord. Well, more than likely that official client was Windows and maybe MacOS exclusive. They built it from the ground up, and sure it has an API and sure a linux client may exist. But it would never be 1:1 with the official client.

This was the most likely thing to happen, and theres no way you can convince grandma to try Linux when all of her basic apps don't work anymore.

Fast forward to 2023. Unless Grandma is using Adobe software, Linux will work fine. Chromebooks sold well for basic users afterall.