I think maybe - this conversation is more about giving some more acknowledgement to the other side of this issue.

It's not that I disagree with you essentially - or particularly with respect to your analysis of your specific examples. 100% in the cases you describe. Those sound like beneficial tests. Particularly because your example SPEAKS to the business case - users were using the help docs (I think you mean users anyway). So yeah - that's important.

But I don't know why it's so hard extracting a simple acknowledgement of what I'm pointing out - specifically that the decisions like implementing tests IS a cost-benefit decision dependent on business context.

Funny you mention auth testing though. One time both me and the tech lead broke one of the auth flows in production within the space of a week of one another. Yep - no tests. Feel free to judge us insane. But here's how we thought about it - and when I say "we" that includes the business. First of all the auth flow was not actually used by any active users, so damage was low. Two man dev team. Complexity up until that point had been low, pre-product market fit, sales were dogshit, and cash had been low for some time. Feature shipping was the 110% priority. Ok - but these bugs were a sign complexity had increased beyond what we could manage without some tests. And given the importance of auth, it was now easy to make the case to leadership that implementing an e2e test suite was worth it. So we did.

If you still think a decision making process like that is insane - because we didn't immediately implement tests for every shipped feature. Well - I just think you're wrong.

There is supposedly a famous video series of Uncle Bob trying and failing to solve sudoku with TDD. He did not read any guides on solving it and tried from first principles instead, and bounced off of it.

It’s clear to me that if you don’t know what you’re building, testing it first has rubber duck value that can easily be overshadowed by Sunk Cost. I always test my pillars - the bits of the problem that are definite and which I will build off of.

Yes, starting with tests without market fit can also be fatal. But calling anything done without tests is just a slower poison. Before you airlift your brain to another unrelated problem you need to codify some of your assumptions. If you’re good at testing you can write them in a manner that makes it easy to delete them when requirements change. But that takes practice a lot of people don’t have because they avoid writing tests or they write the exact same kinds of tests for years at a time without every stretching their skills.

If you’re not writing tests you’re not writing good ones when you do. Testing is part of CI and the whole philosophy of CI is do the painful parts until you either grow callouses or get fed up and file off the scratchy bits. To avoid testing is to forget the face of your father.