In s case where you’ve got an experienced player using a deck they’re familiar with, yes turn 1 can & should be quick. But there are lots of cases where that shifts: new players need to read the cards in their hand turn 1, just to see what they do. So might an experienced player drafting an unfamiliar set, or running a new deck that they copied off a list. The other day I took 10-15s to think on turn 1 when my opponent dropped a Mobilized District as their first land (Are they really on a Colorless deck? What’s that list likely to be? What’s my plan against that? etc). And the risks of shortening the time here are harsh; getting auto-passed through turn one and missing your land drop (or getting flustered and playing the wrong land) is a huge setback for the player.
I get that players that tank forever to decide to drop a Mountain are annoying, and I’m not giving up on finding a way to help that, but there’s a lot of splash damage to consider here.