No, there are plenty of guns that have a direct blowback bolt and fixed barrel .

The problem is increased recoil and weight from a heavy bolt. The tilting barrel slows down the unlocking of the barrel from the bolt so that more of the gas escapes out of the front end of the gun and it doesn’t blow up in your hand.

Some guns use heavy bolts, some guns use tilting barrels, some guns use rotating barrels (or bolts).