> The problem I observe is the universal one: management doesn't care about good code, it cares about results. It's generally too hard for ANYONE to tell what's going on in a codebase unless you're experienced with it. Management can't evaluate the value of maintenance work, so it doesn't value it.

I think this is a very telling statement, but perhaps not in the way you intended. I would agree that management only cares about results, but I would posit that maybe that's a good thing. If you don't have ground-truth knowledge of a problem, you must rely on either the word of someone who does, or metrics that can be used as a yardstick.

When all a manager has to go on is someone's word, it can be really hard for them to gauge the depth, severity, and impact of the problem being expressed to them— and without any metrics, they have no way of tracking progress on resolution. In a modern codebase, you could spend YEARS on improving maintainability and still not "finish". The key (that I've found, personally) in this situation is to give the manager some form of metric to describe the problem. If you can establish a number to measure what you're advocating for, and quantify the consequences of not doing it into actual business impact, I've talked managers into taking my suggestion more often than not.