Yeah, I admit. A better analogy on my part would have been that you buy a car and it's not street legal anymore, or one that does not work in today's environment anymore. "I don't want to add seat belts, just drive" or "I don't want it to run on unleaded fuel". (Note that I have no idea if there actually were cars that required leaded fuel.)

Anyway, I think even more likely than running into new compiler warnings/errors is running into external dependency issues, which require you to touch the software anyway, and, I'd argue, are often much harder to fix than fixing code that triggers warnings.