It's faster to go from the 50th floor of a building to the bottom by jumping out the window than it would be taking the elevator, but that just makes a mess of things. Similarly, you seem to be going faster with AI, and in some respects you are, but there's also the matter of technical debt, which is the messy aspect that someone has to deal with later.
I have used AI to quickly write up small functions here or there, but even then I've had to go in and clean up the code because even in small tasks it can be messy. The mess scales with the size of the problem, even if you do split it up among more agents (in fact it can be worse if you use too many agents).
Especially when people claim 10x productivity gains (a suspiciously oft-repeated claim, by the way), alarm bells ring in my mind, because I've seen the garbage that AI generates, and no one is actually reading that garbage carefully and cleaning it up while maintaining 10x productivity.

You may not like it, but this is what 10x productivity looks like.