"Yes and no. If you don't need to make changes to a given system then it's fine for it to "rot". Presumably there is a business reason they want to make changes

"Yes and no. If you don't need to make changes to a given system then it's fine for it to "rot". Presumably there is a business reason they want to make changes, in which case bringing the code up to a point where you can make those changes is part of the cost of that business-level deliverable." Except at that point, there's likely a hard (usually arbitrary) deadline, meaning you don't have the time. So you end up hacking stuff up again, and the tech debt doesn't get addressed. Your best people end up getting frustrated that they're not being listened to, and that they constantly have to explain this stuff to the business people, and eventually they leave.