Salesforce stock is down with the rest of the market and not as appealing as an acquisition tool as a result (they also paid a lot for slack). They also already play in Zendesk's space (eg service cloud) and tend to buy what they don't already have.
Ehh....in the time I was there, they bought Tableau _and_ Datorama in the same month, and they already had reporting/analytics features (although not as in-depth).
They also bought a dozen or so machine-learning companies that all did similar (or even identical) things over the span of the 5 years I worked there.
Famously, they bought Heroku, and then completely ignored it (including internally -- there were efforts at one point to have Heroku be the "way forward" for internal development on PaaS providers, and they scrapped that entirely while keeping Heroku more-or-less running).
I'd say Salesforce tends to buy whatever shiny thing gets Benioff's attention for the moment, usually because he talked to somebody at a conference. The guy tends to ram through quite a few questionable business decisions, and these days Bret Taylor's job as "co-CEO" is mostly "cleanup crew" for Benioff's various whims.
Without going into much detail, the way some NFT stuff was handled internally is a big example, and then there was the company all-hands where Benioff berated some presenter on stage for having not-cool-enough shoes, and Bret had to spend a whole trying to spin it into a "haha, great joke buddy" sort of situation.
Stuff like Benioff's "just the tip" tweet has always been who he is when his handlers don't have a tight grip on him. Bret Taylor's position seems like he's been put there because 1.) He's got _some_ engineering experience more recently than 1999, and 2.) Bret is less, uh, belligerent than Benioff.
