They been talking about this for a long time.

In fact, I remember at some point, they were trying to sell the idea of exposing all the form inputs to use the `::part` API, since under the hood form inputs share the same general logic of custom elements, If I recall correctly.

From the looks of it, didn't work out that way though.

And I think its for the best. I like this proposal more, even though delivering the `::part` API to everyone (not just web component users) would have likely been faster

Using ::part() was a bad idea. Part is for user-defined pseudo elements. The platform can just define real pseudo elements. I argued against using `::part()` in spec threads, and I haven't looked back recently, but I think that argument won over.