This is the "dumber but honest person that works harder" phenomenon, vs "lazy genius".
Sure, in the future full rewrites and stuff like that will be just another "throw money at it" problem, but fundamentally software can get arbitrary complex and we barely know how to write large, maintainable code bases.
Nonetheless, I think testing (and maybe proofs) will have its long-awaited time to shine, as being the "reward function".
Right now, I put models in low thinking mode during my refactors and hate waiting. I would much rather have a faster model that that maybe was slightly stupider, and I would wait far less long between prompts where it needs my valuable input.
Models that are dumb, but humble and fast, can be fine.