... It was made doubly stupid by the fact that Superman was accompanied by all sorts of other heroes, none of whom figured out that you could actually pick Doomsday up (like if you had a POWER RING, SAY) and throw him into space.
Nono, you don't get it. Doomsday is too strong, so that wouldn't work. You can't throw him into space, you can't transport him to another dimension, you can't even put him in the Phantom Zone. He's just too strong. Got it?
Supes tried to put him in orbit and got a nasty side wound for his trouble. The creature wasn't just strong, it was also just as fast as Superman was. C'mon, the Byrned Supes wasn't exactly good at fighting those who were just as strong/fast as he was. He got his butt handed to him by an intoxicated Lobo and almost got choked to death by an inexperienced Lar Gand.
The Byrned Supes didn't have access to a Phantom Zone projector until the Loeb crew came onboard IIRC.
And the variation of the JL that accompanied him? They were a sad sack of incompotent lightweights.
As for a power ring, that might have worked if Guy Gardner wasn't a moron.