I agree Google has too much market share and sway over plenty of browser features.
However… CSS features are a W3C specification and are an early stage [1]. It’s a process that vendors draft and agree on and can terminate.
On top of that I wouldn’t characterise improving css with functions isn’t a _churnful trendchasing_. If anything this will improve accessibility because it’ll be easier to manage size, colour, and motion preferences with better abstractions than media queries everywhere.