People really don't understand the cost of bit rot -- especially business people. If it worked 10 years ago, and it hasn't changed, why can't we use it now? I happen to have an old Rails project that my team has to maintain. Rails 2, Ruby 1.8.7. When we stopped being able to even compile Ruby 1.8.7 with the latest versions of GCC, I finally got approval to upgrade.
Things that business people can't understand is that nobody supports the language version any more and you can't build it with modern tools. You can't run the old OS any more, which has the old tools to build your code because the OS doesn't run on new hardware. I've been in the situation where I've had a server that was practically unique. It was so old that the only hardware that could run it, was the machine that was already running it. If that died, it was game over. (I should probably mention that I tend to specialise in difficult legacy situations in my career ;-) ).
The idea that you need to do maintenance work on your software, even without fixing bugs and without adding features, is incredibly difficult for business people to swallow. So they naively allow the situation to get very, very bad (and then they have to hire someone like me).