Firstly, I don't know how you conclude Safari has the majority of market share on Mac.
> Chrome is convenient, but I'm not about to start using Opera or Safari because Google is making a better browser.
Chrome uses far more battery and processing power to achieve the same task as Safari. Safari animates content smoother and scrolls pages smoother. I would conclude Safari is currently the best web browser, despite it being slightly behind Chrome in standards support.
> ignoring standards like "filter: blur()"
This is false.
> implementing their own "backdrop-filter" that no other browser uses
This is false. Backdrop filter support is planned in all browsers except Edge currently. You can enable it with a Chrome flag. I should also mention it is a huge advancement for creating blurs on the web.
> Chrome and Firefox are the leaders in feature advancement
I don't see how you can consider Firefox a leader anymore. That browser is a mess, hopefully they make a comeback.