FB has done a lot of great things. There just aren't any articles written about them.
Google's culture is hire 15 geniuses from the Ivy League with 130+ IQ and make them fight with a 40 minute C++ build and a balky Kubernetes culture because "we only hire the best"; YouTube and the advertising system are a money printing machine, the team works for 3.5 years at something that get canceled at the last minute.
Facebook is much more oriented towards greasing the skids with the goal that a fresher developer would be able to push a change to a shared development system the first day on the job.
Look at React vs Flutter.
Like Microsoft, Google is thrashing around looking for "the next big thing", sometimes like a mindless beast. I've met person after person who told me that they went there because they believed they could make an impact and came to the conclusion within a year that they couldn't make any impact at all.
Facebook on the other hand is still run by the founder and it is pushing hard to develop a technology that he believes in even if the rest of us don't. It's a riskier strategy than Microsoft or Google who are likely to stumble on another multibillion dollar business despite themselves.
The idea was you make the change, take a screenshot of the result on your dev instance, get it stamped by your “mentor” and then abandon it. AFAIK this had been going on for a while before I got there.
Fast forward a few months and I see a sev pop up. “Default text on www.facebook.com search bar says ‘I am a search bar!’”
I have mixed feelings about marketing to the enterprise market. On one hand you can build some large and interesting things that deliver a lot of value, particularly in the semi-custom area. For many reasons I can understand the viewpoint of a salesman on commission. On the other hand I was really depressed after I'd talked with about 20 vendors in the "enterprise search" space and found that none of them particularly cared about search relevance and didn't regularly do evaluation work unless they were participating in TREC to gain industry visibility. Sometimes enterprise products have a lack of refinement or even basic quality compared to consumer products.
If I was going to get back into business development I'd do it with a keen understanding that getting the politics right and the software wrong is better than the reverse when it comes to making a living. I think I'd find myself hard to motivate in that situation.
I think Microsoft's end user area where they are the most pathological now is XBOX, Game Pass and all thought. Looking from the outside it looks like Dr. Evil has decided to buy the whole game industry to put it out of business and force people to pick up another hobby.