Earlier quoted context omitted.
None of us do "guardrail driving", but we still put guardrails on roads.
However, on most highways the guardrails are only on the dangerous sections. So sticking with this analogy, we should only need to use testing in the more intricate / complex parts of our code. However, current testing best practice seems to be to test everything possible, thus potentially wasting a lot of time and effort into aspects with a low ROI. There could be some lesson in this...
When I first started testing it seemed like the world suddenly got really scary and now I had to test everything. I ended up testing ridiculous stuff, things that the language would provide by default. (I did this in many languages which is why I don't mention a specific one).
What I've found valuable as I do testing (I do TDD) is that it has made me change how I think about design and composability.
I agree that there should be a greater focus on "what is appropriate to test" but even knowing how to write tests and what to test is a skill in itself.