In the past this was a major issue that meant useful features were only ever usable after IE/Safari finally supported them half a decade later, but it has seriously gotten better. Sadly as a result of Chromium's overbearing presence, but it's a helpful outcome at least.https://wpt.fyi/interop-2025
presentation|14 days ago
graypegg|13 days ago
Saying that, MacOS and iOS generally (up until recently, from what I've heard) have very good uptake rates for major updates. It's become less awful standards-wise as time has gone on in my experience at least.