They landed an earlier version of the second stage on the ground a few times as well. It's the atmospheric reentry from orbital velocity that currently necessi

They landed an earlier version of the second stage on the ground a few times as well. It's the atmospheric reentry from orbital velocity that currently necessitates the safety of a splashdown: they're not going to risk bringing a damaged and potentially uncontrollable vessel down over land, even if they could nail the landing with an undamaged ship.