Earlier quoted context omitted.
I'm not sure if it's Google's fault alone. My impression is, all browsers are holding back on everything HTML-native and JavaScript-free. There have been literal decades of no progress, and only tiny steps forward as of late. We've had things like https://doc.qt.io/qt-6/qtwidgets-module.html since the late last millenium. Back in the day, there was Delphi, now there is Lazarus, with even nicer Data-Bound widgets. Loo…
My guess is that it takes time to research what universal behavior users expect from a component based on examples in existing software. It's universal, so it has to work with everyone: mouse, keyboard, touch; large monitors and tiny phones; screen readers; and users with motor difficulties. And existing components may not have even thought of all of these cases. For example, they've recently introduced the Interest…
Maybe VR glasses will be big soon. Do we trigger on 'blink'? 'look harder'? 'eyeball wiggle'?
Maybe voice interfaces? Trigger on 'say it louder'? 'stuttering'? 'hesitant'?
Maybe guestures, facial expressions, thought patterns? 'think hard about that button to trigger tooltip'? 'furl your eyebrows'?
As I've said, decades have passed with no progress. If progress in other fields is a reason for waiting, it'll be stagnant forever and eventually just dead.