Was thinking the exact same thing. My hypothesis is that Facebook is behind because just as the Red Book suggests, its overall culture has been to build things primarily for people (freeloaders), and not for enterprises (who are actually the ones paying) like Microsoft (originally) and Google (eventually) do. If you look at Microsoft and Google, a lot of their garage projects are to build products that are useful to enterprises first and are hence more successful because it's easier to bring in cash with them. Their end-user products, meanwhile, eventually end up getting extinguished.
I worked at a Microsoft shop circa 2007 on ASP.NET/Silverlight systems and we had a subscription to MSDN. This was a pretty good value in terms of the headliner products like SQL Server, Visual Studio, Sharepoint, etc. We were getting discs for everything in MSDN and had a cabinet filled with discs and had an employee whose job it was to catalog it. I was amazed how many discs we had of enterprise software from Microsoft or some company that Microsoft had bought that I'd never heard of we had.
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.