Actually, ad agencies are just as concerned as the advertisers. Measured by results: sales increases and the like, most agencies loathe this phenomenon. Yes, full disclosure, I work for one (I know, I know: here, have some snake oil). Anyway.
We frikkin HATE this crap. I spend my day deep in analytics, trying to work out how get the right ads in front of the right people and have shit like this to deal with. I'd rather buy 1 piece of adspace and have it go to people who actually care about the product my client is selling than have to try and navigate this bewildering world of crap. Yes, it affects our bottom line (media spend goes to Google instead of allowing us to do a better job on the actual ad), so yes we hate it. Yes, it affects our bottom line because our clients don't have trust in targeting, so are tempted to spray and pray whilst bitching about cost per acquired customer: as if that's something we have any control over (because of scams like this). And you suffer because you get a million completely irrelevant ads that clutter up your browser.
Yes. I really would rather make just one ad and send it to exactly the right people. You'd get fewer ads, we'd get to make better ads (better engineered, faster loading and less buggy too because we'd have the time/money to spend on it) and our clients get the customers they need.
And if you don't think advertising is necessary for the modern economy to actually run then you have *never* run a business. I have.