Philosophically (and, I think it's legitimate to say, morally) I agree with the desired outcome. But I think we should not underestimate the forces that will be unleashed by the adtech complex -- precisely if/when it is threatened with widespread extinction and precisely because of the incredible (literally) amounts of VC capital that have been sunk (literally, in many cases) into these companies. Someone must have said once that, in a capitalist system, it's very bad to have desperate capitalists as enemies. (If not, I'll take it.)
Specifically, I predict that you're going to see some extremely clever and well funded efforts to expand the legitimate interest ground into . . . if not the get-out-of-jail-free card that some (like the DMA) are already claiming it is, then at least into a very, very large lifeboat that can keep large parts of the adtech ecosystem afloat even as the ship of surveillance-based advertising formally sinks after striking the GDPR-berg. (Flaw with this analogy: Everyone
knows that the GDPR-berg is sitting there, and yet, unlike the Titanic, they steam for it
on purpose!)
For example, as I've said before (I think; I lose track of what I said on which forum), it was very odd that when industry lobbyists met DPAs in Madrid recently to discuss (among other things, but this dominated) legitimate interests, the lobbyists studiously avoided even acknowledging the existence of the 2014 Article 29 WP opinion on legitimate interest (WP217). Why would they do that? Because that document spells out in considerable detail how and why LI cannot (ought not) be used to excuse surveillance-based advertising -- and they want to fight the battle anew. (Fortunately, the DPAs and other EU data protection authorities in attendance were not shy about quoting from WP217.)