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.
Were you going from junior (L3) to intermediate (L4)? If you were, then the task you described seems appropriate - you don't have to do much to go from L3 to L4.
The author of the blog post was going for senior (L5), which you can't get just by maintaining code.
To be fair, a lot of that can depend on your manager. Your manager (should) have a better perspective on what resonates with the committees, help you gather/frame the data, and polish the package.
Google managers might not be the ones doing the promotion, but a good one can help you get there
Because you didn’t show graphs but showed testimonies form actual humans. Which I would assume, I don’t know for sure, that business people see graphs or hear grand ideas all day long and just really wanna know “yeah but is this actually improving anything for anyone?”
Well, glad to hear the system rewards good, unglamorous work sometimes!
I think a piece working against me with the pipeline was that it was kind of an oddball part of the company. The clients of the pipeline were all external researchers and the data was all free, so I couldn't point to increased sales and the clients couldn't write me recommendations for promo.
I think I would have had better chances if my clients were other internal teams who could say, "Yes, this pipeline is much more stable now."
I can't say why it worked only for one of us.