I agree that it could be worse! Facebook has significant (if not more) time spent and I found adding features to news feed a heck of a lot easier than adding features that interacted with google search. Generally a lot of this had to do with the number of people needed to be involved to ensure that the change was safe which always felt higher at Google.
I'm only an outside observer in this conversation but could it be that the review process (or the lack thereof) and the ease with which you can add new features has had an impact on the quality of the software?
The thing is, in my experience as a user Facebook (the product, not the former company) is absolutely riddled with bugs. I have largely stopped using it because I used to constantly run into severe UI/UX issues (text input no longer working, scrolling doing weird things, abysmal performance, …), loading errors (comments & posts disappearing and reappearing), etc. Looking at the overall application (and e.g. the quality of the news feed output), it's also quite clear that many people with many different ideas have worked on it over time.
In contrast, Google search still works reasonably well overall 25 years later.
There are pretty different uptime and stability requirements for a social product and web search (or other Google products like Gmail). When news feed is broken life moves on, when those products break many people can't get any work done at all.
One of Google's major cultural challenges is imposing the move slow and carefully culture on everything though.
I have the same background: I find the code quality at G to be quite a lot higher (and test pass-rate, and bug report-rate lower) than News Feed, which was a total shit-show of anything-goes. I still hold trauma from being oncall for Feed. 70 bugs added to my queue per day.
The flip side is of course that I could complete 4 rounds of QuickExperiment and Deltoid to get Product Market Fit, in the time it takes to get to dogfooding for any feature in Google.
