The rumors from inside Google is that there's no way to get credit/be rewarded as an employee simply for maintaining an existing solution, or even for fixing obvious breakage. Every incentive is tilted towards starting new projects, often multiple projects in the same domain directly competing with one another. There are some positives to this of course, but clearly it's being overdone.
But still...As a prod manager,you aren't coming up with new projects every week, your entire job is to ensure the roadmap is decent and not taking the product into the graveyard. The company has so many people and yet can't produce a single product with a decent UX.