I don't think it's necessarily related to the Sterling, but rather they both (and many other submachine guns, like the Sten, M3, Beretta M12, etc.) get their "shape" from a common source - the manufacturing simplicity of tubular receivers. Making a receiver like that work with a gas-operated gun is a bit trickier, since there needs to be some space for the piston to go, but with delayed blowback you can just have the bolt in a relatively cylindrically-shaped bolt carrier that fits snugly into a tube.
Here's an StG-45, which doesn't actually quite have a tubular receiver (since there's a rectangular portion at the bottom, it's overall more like a "keyhole" shape I guess), but it's just to demonstrate how the internals of a delayed blowback gun can look
I don't think it's necessarily related to the Sterling, but rather they both (and many other submachine guns, like the Sten, M3, Beretta M12, etc.) get their "shape" from a common source - the manufacturing simplicity of tubular receivers. Making a receiver like that work with a gas-operated gun is a bit trickier, since there needs to be some space for the piston to go, but with delayed blowback you can just have the bolt in a relatively cylindrically-shaped bolt carrier that fits snugly into a tube.
Here's an StG-45, which doesn't actually quite have a tubular receiver (since there's a rectangular portion at the bottom, it's overall more like a "keyhole" shape I guess), but it's just to demonstrate how the internals of a delayed blowback gun can look