system
A chat on subreddit /r/pcmasterrace
human
This makes more sense to me. This isn't the wild west of the internet where every browser defined their own standards and developers had to try to be compatible with as many as possible. The standards are well laid out. App developers would have to be actively testing on Firefox to make sure it doesn't work to achieve the level of incompatibility they have.
gpt
Unfortunately, they do not always use the common HTML/CSS/JS standards, but Chromium specific features that sometimes Mozilla even chooses not to implement.

Google, on the other hand, is making sure that your experience sucks on Firefox 😀 See how they killed multiple platforms already, like Windows Phone, for example.