Cost/benefit. If 95% of your users are on Chrome, that's where the business wants you to spend most of your development effort. It's the same issue with game dev. Most games don't support Linux natively because the small user base doesn't justify the time sink for developers.
Not saying I like it, but I'm not surprised at the current state of the ecosystem.
All developers should understand basic web standards, particularly accessibility.
Have you worked with Angular much? I've built extensive component libraries (internal) for my org and maintaining the Angular one has been a nightmare. The frequency of breaking changes and conventions has been awful, particularly in the last few years. React, by contrast, has been a breeze ever since they introduced Context and Hooks.
On the app development side, we dealt with 3 major overhauls of PrimeNG's style system before we decided to invest in a custom library just to eliminate the risk of future upgrades. It took us 6 months to migrate our Angular 9 app to 18 because of the PrimeNG dependency. Granted, it's a massive application and they didn't maintain it properly, but I'd hardly call Angular stable regardless.
And then you have the Vue composition API, which was a major shift from Vue 2.
This isn't to say that React has been perfect. Depending on your stack, there are certainly a fair degree of breaking changes (looking at you, Next.js and react router). But that is far from abnormal in the JS world.
I don't think so. I have a P16 Gen2 and this thing sucks power like nobody's business. 13950hk and 128gb of RAM. I barely get 1 hour of light programming work. I mostly use it as a desktop though, and I have a separate M2 Mac for traveling.