Having lived through the screeching halt, I agree. There reaches a point where you genuinely cannot make a change without breaking something on the live system,

Having lived through the screeching halt, I agree. There reaches a point where you genuinely cannot make a change without breaking something on the live system, or taking five times as long as is reasonable. You no longer have any idea what the real behaviour of the system or why (doco is NEVER up to date). Not having tests was part of the reason I changed jobs. I don’t know why people assume that tests hold you back from changes. If they do, they were just bad tests which were testing implementation details rather than businsss logic. That’s an argument to not write useless/stupid tests, not an argument to not write any tests at all. It just seems to be far more difficult for developers to decide what a good test should look like than to decide what any other good code should look like.