In fact, in my experience, these elaborate test environments and procedures cripple products.

I'm firmly of the opinion that if a test can't be run completely locally then it shouldn't be run. These test environments can be super fragile. They often rely on a symphony of teams ensuring everything is in a good state all the time. But, what happens more often than not, is one team somewhere deploys a broken version of their software to the test environment (because, of course they do) in order to run their fleet of e2e tests. That invariably ends up blowing up the rest of the org depending on that broken software and heaven help you if the person that deployed did it at 5pm and is gone on vacation.

This rippling failure mode happens because it's easier to write e2e tests which depend on a functional environment than it is to write and maintain mock services and mock data. Yet the mock services and data are precisely what you need to ensure someone doesn't screw up the test environment in the first place.