Not really. Having heterogeneity among operating systems is better than pure homogeneity. Say, if everyone ran Linux, and some massive security flaw was discovered, we would all be screwed at the same time. However, if we ran different stuff, and some massive security hole was found for just one operating system, then only a small portion of the world is vulnerable at once. Besides, more operating systems can lead to more innovation, as long as there is good competition between them.

just works, is easy to use, easy to configure, doesn’t require an IT degree to use, and that we can recommend to our grandma

TempleOS satisfies all of these conditions

For real though. I swear, some of those animations are more detailed and well-animated then anything Pixar could produce.