For the record, there's already a bunch of custom select-a-like replacement elements out there; I'm partial to select2. The main reason for this is that selects don't come with what we used to call "combobox" features; there's no type-ahead completion, and you can't lazy-load options from a larger data source because of that.
My main gripe is the loss of rendering outside the browser pane. To be clear, we already don't have that on mobile at all; if you've ever used an iPad with Stage Manager you'll note how popovers - all of them, including native apps - are neatly conformed to the bounds of the containing window. Pop-over menus are supposed to break the window pane, but they don't, for reasons I don't quite understand but can guess rhyme with the word "security".
My main gripe is the loss of rendering outside the browser pane. To be clear, we already don't have that on mobile at all; if you've ever used an iPad with Stage Manager you'll note how popovers - all of them, including native apps - are neatly conformed to the bounds of the containing window. Pop-over menus are supposed to break the window pane, but they don't, for reasons I don't quite understand but can guess rhyme with the word "security".