I'm also a Googler. Upon joining I was also given the keys to an ancient data pipeline, due a redesign for at least five years at that time. The person handing me the keys left almost immediately. My task was also keeping the thing adrift and nursing it back to health, whatever it takes. I did get promoted for that. The metric I used was pretty much the amount of developer time that went into supporting it that was saved by my damn ugly hacks. It was collected by asking nicely for the affected folk to confirm their lives got better.

I can't say why it worked only for one of us.