I would say that Googlers can make time to fix things. In the parts of Google I've seen, engineers are largely given projects with a timeline of weeks or month

I would say that Googlers can make time to fix things. In the parts of Google I've seen, engineers are largely given projects with a timeline of weeks or months and left to structure their time themselves. You're usually given more projects than can feasibly be accomplished in the time allotted, and learning which are high priority and which to let slide a quarter is a bit of an art, but as long as your projects are moving forward you can usually structure some time for paying down tech debt or a side project, either an official 20% or just experimenting with your area of responsibility outside any roadmaps. I tend to structure my weeks with Tuesday as the designated day to fix anything that's broken or, if everything is running smoothly, to pay down tech debt more for the opposite reason, so that I don't get caught in a rabbit-hole of fixing things that aren't broken and neglect to make progress on the new work.