I find this evolution fascinating. It makes sense to me that the GM model worked for so long. If much of a company's advantages were cultural, you could put together teams that could out-compete startups within a large organization. Procter and Gamble needs to enter new markets with new products to grow -- there's only so big a market for soap or razors or drills.
But lots of tech companies today have a significant scale advantage. Google ads is most of their revenue; Netflix has a single product. Functional expertise that drives a 2% gain across the entire business is possible and valuable.
So ... why does Twitter want to go to a GM model? Are they watching Meta have success diversifying from Facebook? Or is there something else?