Earlier quoted context omitted.
> It takes maybe 5 minutes to download and install Classic Shell and suddenly you have a classic UI 1. Where would a user even learn about a "Classic Shell"? 2. Why would a power user install a third-party thing that radically changes the way the system looks? And one whose development stopped in 2017? 3. And, in general, why? It's the OS' job to provide interfaces for power users.
1. Google old start menu . It's literally the top result. 2/3. Sigh. I didn't realize setting up Classic Shell was so much harder than setting up a Linux box for a power user, I'm sorry. Power users definitely should be the ones to expect their OSes to be perfect for them out of the box, and it's definitely nuts to expect they'd be the ones to customize their systems.
People in the know are aware of Classic Shell. Most people aren't. Most people won't take any remedial actions or even find out that there are options; they'll live with it, hating it, and despising Windows even more. The number of people who go to the effort of installing Classic Shell is a tiny minority of the total userbase.