The Safari/WebKit people are doing good work, yes.
I use Safari as my default, and like every Firefox/Safari user I still get some bugs that don't occur in Chrome (not talking about WebMIDI obviously), so watching that 30 point gap between stable Safari and bleeding-edge WebKit (longer than 7½ weeks) on wpt.fyi was quite frustrating. The average Safari user would have a better browsing experience with a shorter fix delay, that's just the truth. Having to wait for macOS updates holds back the browser, unnecessarily.
The bugs aren’t necessarily the browsers fault.
> Having to wait for macOS updates holds back the browser, unnecessarily.
Safari is an operating system component, which lots of people don't seem to understand; hundreds of thousands of 3rd party apps rely on Safari's WebKit engine.
I've never heard a normie Safari user complain that Safari updates aren't being released quickly enough; that's something web and app developers care about… which is why Safari Technical Preview is released every two weeks.
Even the release versions of Safari on iOS, iPadOS and macOS allow you to enable web features that are still in development.