It’s all about identifying the ultra whales willing to spend thousands a day. There’s an infamous story of a machine zone employee being stopped on the tarmac by the FBI trying to flee with a thumb drive full of IDFA’s. GOW had people dropping millions, and you could eat their lunch quickly with a fast follow and best customer list. Not sure it was ever publicized, but I’ve heard that story a few times
Insofar as they're tied into the online advertising markets, yes. You need to collect the data for good ad revenue, and in-app purchases don't typically pay the bills on their own, so there's an incentive to collect data. Since the actual collection tends to be via libraries, it's relatively easy to ignore what your app is actually doing.