Its hard too. my current job with a large existing code base (perl/python/shell scripts and java), and keeping it up to date is a large portion of my time.
The thing is I get very little credit for fixing something that is broken, but creating something new generates accolades and the illusion of productivity...
That's the problem of being a maintainer. You point at something and say "that's still working", and no-one knows if it's because nothing has happened anyway, or because you ended up fixing some fatal error in it.
New features are also pretty easy to measure in terms of throw money in, get features out. Maintenance... how hard do you go? How much is too much? Do you just need a light check-in? Do you need full reviews? Or is that just wasting money for no reason?
The thing is I get very little credit for fixing something that is broken, but creating something new generates accolades and the illusion of productivity...