Really simple example.
Runner on first, 1 out. 2 outs to get 1 extra base hit.
Runner on 2nd, 2 out. 1 out to get 1 singe.
Odds of those things happening is roughly the same. The bunt is basically treading water. Of course, leaving the guy on first base gives you an extra plate appearance for a single that would advance him to 3B or an unintentional sacrifice as well (and a double play, of course).