Test suites are one leg of the stool. The others include memory safety, type safety and (for real-time applications) resource guarantees, as well as a formal development process that includes rigorous code inspections. Put everything together and you have "space shuttle computer" level investment required. As you give up legs, the stool becomes cheaper yet not as sturdy.

The problem with that is the economics for many applications don’t favor elaborate test suites. If you’re building a saas software product where you can detect a bug, fix it, and deploy in a matter of hours, and wherein developer velocity is among your most important metrics, an elaborate test suite is a liability (note that the suite spot is not “no tests” but somewhere in the middle) as it makes changes slower. Dynamic languages work reasonably well for these categories of applications, although some static typing can help improve that iteration time.

Having done TDD for 10+ years, I've come to realize the main value test brings is not the error checking, nice as it is.

The biggest value to me is that you can easily do huge refactorings with a lot of confidence. That in turn means you can keep redesigning your code and frameworks long after they would ossify into legacy code no one dares change in a normal project.

That's not to say I disagree that much with your point.

If you give someone $1000 for each bug they find they would find tons of bugs. So in the end its a matter of time/money.