<< Reliability and POWER... sure the Desert Eagle's got a big ol' 45 and there are some funky 10mm semiauto pistols out there...
But it seems that only revolvers can have enough material withstand the tremendous chamber pressures reliably. >>
If automatics were having problems withstanding the chamber pressure, they would explode in your hand. As long as the barrel is not fouled (and by fouled I mean totally obstructed, not dirty), this rarely happens. BTW, the Desert Eagle is chambered in 50 AE, 440 Corbon, and 357 Mag, not in 45.