Google is not protecting its users privacy, it is protecting their own business. They want everyone's ads to be worse than Google's, so you use Google. Hiding private data from everyone but themselves is part of the plan.
That would be check mate for all other advertisers.
I'm just not sure whether it's good or bad that antitrust regulators won't notice before it's too late.
I'll take that benefit even if it tilts the advertising table in favor of Google. I don't care even a little about the overall health of the advertising/marketing industry.