I have no romantic attachments to Apple in particular, after all they were the SOBs that provided IDFAs and set the initial policy, which is why this was a “friendly reminder” on what this policy going forward is and what it isn’t. What appears to you to be a “scary dialogue box” appears to me to be an adequate and accurate description of what IDFAs are used for and why Apple provided IDFAs in the first place. Tracking users and across apps and websites from different companies is IDFAs working as intended.
Now you can be as cynical or romantic about why Apple is doing this now as you want, to me it’s a half-step towards correcting a mistake they initially made, and to others it is clearly something else, but let’s not kid ourselves into believing that just because Apple stripped the paint off of an advertiser’s favorite toy that this is somehow going to be the death knell of user tracking and the app-based advertising industry is doomed on iPhones and iPads. Facebook and Google are big boys, they may not like this new change, but they’ll learn to adapt around it because adapting to new situations and facts on the ground is just another cost of doing business. Business plans aren’t set in stone since time immemorial, sometimes they need alterations to remain relevant and operable.