But for a lot of things, this is actually generally acceptable. Back office business apps, for example, where because of internal politics and attrition, they generally end up being replaced wholesale every 5-10 years, which is approximately how long it takes technical debt-ridden code to become so brittle it's unsupportable. A CIO can save millions by allowing this behavior. Thousands upon thousands of apathetic IT staff (including programmers) make decent livings in enterprises like this.
5-10 years? In a company of what size, in what industry? For most "back-office" apps you're talking 2 years for the re-write just to see (almost) feature parity, and another year for the users to be trained and feel comfortable with it. If you were ripping and replacing a non-technical users go-to app every 5 years you'd have revolt.
We have 2 apps that are used for the same thing.... the original one and the rewritten one.
The rewritten one was coded up in C# over 3 years and isn't anywhere near as robust as the original one.
The original one was written in VB3 circa 1995 and dragged to VB6 where its stayed to this day.
Theres that much technical debt on the old app that the first change I made to it 5 years ago caused it to stop compiling because of the single line I added to a function which made it to big to compile.
If you work in a shop that has been around long enough to lose its training wheels and get a driving licence, then you have technical debt thats core functionality that everyone is scared of breaking.
Anecdotal example: The place I was working at had high software quality standards, but eventually created a separate team that wrote in a bizarre XML 'language' of sorts. This was, in effect, still part of the software, and the sins committed there were horrendous, but all was allowed in the name of "business value".
The end result of that being that you couldn't really change _anything_ without it breaking any of N client installs (each custom) - and you couldn't reason about which one touched a particular part of the code, or what assumptions it made.
That company was all but dead inside two years. There were other factors leading to its demise, but far and away the biggest issue was the crippling technical debt that was piled on with reckless abandon.
There are definitely trade-offs to be made, and sometimes it makes sense to take on some technical debt. Your example of back-office apps may be one of them, but there's certainly a subset of software development for which this is both a business and technical-level suicide.
