From: Southern California
Biggest problem with strategic bombing is the opportunity cost, even if the numbers can be made to work with high tech bombers.
MPPs spent there can't be used elsewhere for greater immediate effect. It's simply an enormous investment that takes much time to pay off.
I just finished a hard mode game against the AI as allies and one of the things that had to be streamlined out of this was the strategic bombing campaign. (It took me 3 tries to beat the German AI at the hardest level, plus a lot of cheese. Strategic bombing is a luxury item at these settings, one which the allies cannot afford. Clinched the win in July of 44, for whatever it is worth.)
It might make sense at lower difficulties or perhaps in multiplayer, but the Allies are on a tight schedule here to beat the AI when it is jacked up. (Key here is to knock out Italy early, as in mid 42, in order to give the Russians some badly needed relief. Otherwise, the beefed up AI can really grind down the Sovs in 42. +2 morale is no joke.)
As for the cheese: suicide the French navy against the Italian navy, and spend heavily on diplomacy (including French MPPs) from the getgo to activate the USA early. You can get them in mid 1940 this way, and you'll need them, too.
WitE Alpha Tester