What did occur, is that advertisers could not be sure of performance so placed more value on the prominence and reputation of the media source. National well reputed papers got the best deals, regardless of real world performance.
It will lead to tight localization again, as advertisers can’t rely on Google just selecting the right people to display ads to, but would have to seek specific sites to advertise on.
The world will be fine.
Remember the "mention this ad and get 10% discount" ads? There you go.
Newspapers did it to some extent, and they were not competitive businesses against methods where tracking does exist.
The reality is that newspapers are still very strong lobbyists, especially in newspapers, as they frequently sink politicians who don't toe their line with unrelated scandal or just plain fantasy. If Google pushes this they are likely to find legislation, particularly in the EU, mandating quite the opposite to what you want.
And then I can buy a 'regular' subscription for google products that comes with actual support? It's like a dream world.
As for messenger, there will probably always be some "free" messaging service out there. Free in quotes as it'll come with phone, isp, or email subscriptions.
I already pay for newsblur.