1) I don't need to 'defend' the system. Targetting works.
1b) "That's a garbage ecosystem and we would all be happier without them."
This is demonstrably false, unfortunately.
The ads power Facebook, Google, much of Entertainment. Almost everywhere you see an ad - that place would disappear without that ad.
So a 'future without ads' is essentially a future without any of those things - and you and anyone else can stop using those things right now, and thereby avoid both the ads and the service.
People chose the crappy ads, with the service, instead of the alternative: nothing.
Granted, there could be more paywalls, but there wouldn't be enough 'pay' to keep the services alive.
2) Yes, I'm 100% telling you that I don't believe your self-assessment of the kinds of ads you see overall. I think most people have no idea of the true inventory they are witnesses, rather, they remember only the tiny fragment that sticks out.
'Your evidence of sense' - is telling you that 'ads are a waste' when 'evidence of a $100B economy' and 'science' is definitely telling you that ads are effective. Even untargeted, or crudely targetted.
3) I don't think it's circular reasoning to point out that many ads are not targeted. You're missing the underlying point - that not all ads land on target, irrespective of how sophisticated the targetting in.
That inefficiency is accounted for in the system.
FYI - as part of 'item #2' not only are you going to be unaware of how many and which ads you saw, you're also going to be completely unaware of their effect on your behavior in most cases.
BMW has been advertising to you since the moment you could recognize their logo, a decade before you could even consider buying a car. That programming 'adds up' to something, no pun intended.
5) Your view of Facebook as a 'parasite' is your own, it's not objective - they have a Billion people who like using it just fine. You're also confusing the collapse of print and the complete commoditization of information, with ads.
I'm going to assume that you've never placed an ad of any kind, and have no exposure to the industry. I'd encourage trying it, even by spending $50 on FB or Google perhaps trying to garner interest in your favorite Open Source Project. You'll learn a lot in the process.
The irony of your ire ... is that better-targeted ads are generally better for everyone - both consumer and advertiser. They are the least annoying and most informative. Though we don't like the invasion of our privacy, the 'targetting' part is really good.