Starfield was likely an important asset and a part of the equation, but I don't believe that Starfield's potential timed exclusivity was the primary reason at all. They just wanted Zenimax, the studios, and its IPs. And that's a fair enough reason. To say that their primary motivation was because Sony's potential timed exclusivity is disingenuous IMO.
I disagree here. While all acquisitions are strategic in nature (they wouldn't spend billions of $ until the acquisitions furthers their strategic business goals), this is very much in line with their "outspend Sony" email. Since that email, they have spent nearly $80 billion in acquisition -- almost 80% of Sony's entire market cap -- money that Sony could never spend.
The biggest outcome of those acquisitions so far has been about making games exclusives and not releasing them on PlayStation.
This is perfectly in line with that strategy.