Because the entire codebase is crap, each user encounters a different bug. So now all your customers are mad, but they’re all mad for different reasons, and support is powerless to do anything about it. The problems pile up but they’re can’t be solved without a competent rewrite. This is a bad place to be.
And at some level of sloppiness you can get load bearing bugs, where there’s an unknown amount of behavior that’s dependent on core logic being dead wrong. Yes, I’ve encountered that one…
Once you gain some professional experience working with software development, you'll understand that that's exactly how it goes.
I think you are failing to understand the "soft" in "software". Changing software is trivial. All software has bugs, but the only ones being worked on are those which are a) deemed worthy of being worked on, b) have customer impact.
> So now all your customers are mad, but they’re all mad for different reasons, and support is powerless to do anything about it.
That's not how it works. You are somehow assuming software isn't maintained. What do you think software developers do for a living?
Nothing I just described was hypothetical. I’ve been the developer on the rewrite crew, the EM determining if there’s anything to salvage, and the client with a list of critical bugs that aren’t getting fixed and ultimately killed the contract.
If you haven’t seen anything reach that level of tech debt with active clients, well, lucky you.
If you can see the future and know no-one will ever encounter it, maybe not. But in the real world you presumably think there's some risk (unless no-one is using this codebase at all - but in that case the whole thing has negative business value, since it's incurring some cost and providing no benefit).
