Phil and the likes were too hands-off on these studios post-acquisition. They got too complacent enjoying steady paychecks over years of delays while working on their niche games that only highlight their artistic vision over generally fun gameplay. That's where they failed. The Activision/Blizzard acquisition and GamePass fumble were just a nail on the coffin
It's also really hard to buy studios and hope to catch future lightning in the proverbial bottle.
Past performance is no guarantee of future success.
Yes, I agree. I empathize with Phil in spirit on it. He's a real gamer and tried to create a space for the developers to do their own thing and create what they want. But it doesn't seem to have been great business.