There are reasons why that's a poor idea. E.g., wider hips pose mobility issues. The system really needs a thorough redesign so that birth doesn't need to fit through the pelvic girdle, but that's far beyond us. The current system was designed for creatures with horizontal body position and small head size. For that it works fine. As it is... it puts strong constraints on development.
Don't think that this is the only place where history impacts evolution, though. Spiders have to drink their dinner because their brain is in a circle around their esophagus (or whatever you call that part of a spider). This worked out fine originally, but spiders became successful, and started growing and getting smarter, so their brains got larger, and now they need a liquid diet. If they get any smarter they won't be able to eat at all.
And speaking of the esophagus, consider the human trachea. Ever have something "go down the wrong pipe"? That's because of a very old design decision that's now apparently impossible to evolve a solution for. The lungs share the plumbing with the gut in the neck and head. There are lots of other similar features calling for a re-factoring of the design, but evolution doesn't work that way. All the intermediates must we not only working, but competitive WRT the prior model. No intermediate regressions allowed. (Except, of course, at times like after a major extinction event, when the selection pressure temporarily becomes quite low.)