[pzhon]

As you pointed out, your calculation ignored the losses/ties due to flushes, straights, and having your hand counterfeited. In total, you only win about 81% of time when the flop contains a card of your rank, with about 8% losses coming from a flopped overset, about 8% coming from your opponent's two outs to a higher set, and about 4% coming from flushes, straights, and getting counterfeited. The 4% makes a significant difference.

Calculations which include these have been done in a few places, and the conclusion is that you need the effective stack size to be about 12 times the size of the call if your opponent blindly pushes the flop.

In reality, in some situations you may be able to extract some value from the times you miss, e.g., when you flop an OESD, or when you can see the turn for free and might hit your set. Position is very important for this. You also can't expect to stack someone with QQ on an AKx board, or AK on a 654 board. Against some opponents, particularly LAGs who will often bluff you out on the flop but who will rarely stack off, no stack depth will allow you to call for set value alone.