It’s because Slott told us that was the point, but he never showed the reader. If anything, what he showed the reader was Otto was objectively better at many things, with Peter voicing awe at different points. Peter didn’t earn his return - Otto just all of a sudden threw up his hands and gave it back to him because, reasons. And then as you point out, Slott made Peter an incompetent sophomoric manchild.
It’s an incredibly sloppy story that lacks structure, resonance, consistent world building and characterization.
I will give Slott props for an intriguing idea. And I think a lot of the reason why people liked Superior is because Peter, ever since OMD, has been frozen into a rubber action figure encased in amber that can never learn, never grow, never have an adult relationship, etc.
At least with Ock, the sky was the limit and the story could go anywhere, do anything. It was truly unpredictable in concept, and that was exciting to readers.
But that’s the concept and the promise of the concept, not the execution which was ham-fisted.