Chrome's compatibility is 100%, because it's defined in terms of compatibility with Chrome. (Despite the fact took 21 years before Chromium got a limited subset of MathML, when Firefox had it from Mozilla 1.)
> I am very much against the monopoly Google has over the web space and their positioning to dictate future web standards
Then, to the extent you can, stop using Google-controlled browser engines. Google can only dictate future web "standards" if they're the de-facto standard browser engine… so just refuse to acknowledge them.
If you make websites, use stuff that only works in Firefox (and the indie browsers), like Content MathML, or stick to stuff that works in every browser – and by that, I mean clean, semantic HTML. Force Google to play catch-up for once, or make the whole "catch-up" game irrelevant.
My favourite such feature is alternate stylesheets. Supported by Firefox, and by basically every CSS-supporting indie browser, but by almost none of the Chromiums.
In terms of compatibility, depends what is being tested. Firefox (and IE curiously) have had far better support for splitting content when printing - Chrome requiring odd hacks to avoid bits of elements overlapping the table header/footer when page split for a very long time (last time I retested the situation had somewhat improved. It still had issues with splitting but content no longer merged making hiding the tbody under the thead easier).
Chrome also deliberately broke CSS2 years after it was supposedly completely implemented to simplify their rendering, breaking existing websites. (this was showcased on their "html5 rocks" website at one point to quite a lot of protest from other browsers). Everyone ended having to follow Chrome's lead at that point, but for a while who was "fully compliant" would be up in the air. Amusingly it seems to me anchor positioning Chrome just added to CSS3 allows doing those things they considered un-performant, a decade later.
Google has also implemented rather dubious specs, like WebUSB where it is understandable no one else has implemented yet due to security concerns - but that would also drag down scores further.
> I am very much against the monopoly Google has over the web space and their positioning to dictate future web standards
Then, to the extent you can, stop using Google-controlled browser engines. Google can only dictate future web "standards" if they're the de-facto standard browser engine… so just refuse to acknowledge them.
If you make websites, use stuff that only works in Firefox (and the indie browsers), like Content MathML, or stick to stuff that works in every browser – and by that, I mean clean, semantic HTML. Force Google to play catch-up for once, or make the whole "catch-up" game irrelevant.
My favourite such feature is alternate stylesheets. Supported by Firefox, and by basically every CSS-supporting indie browser, but by almost none of the Chromiums.