I have to believe a LH hitter should be able to average .500 on fair bunts against a shift.And a foul bunt is simply a strike, not an out.
And once again, the bunt doesn't have to be perfect.It doesn't even have to be good.
It has to be fair, past the pitcher, and not both too hard and directly at the only fielder on that side of the infield.
I gotta believe just about every LH hitting major league player can get that bunt down more often than not.
Soooo...why don't they?
And if you screw up the first bunt with no strikes and send it foul, there's a good chance you may not break the shift but you've moved the fielders over a step or two, opening up more space to swing away with one strike.