So now the government is going to force a separation into multiple companies and by doing so increase user tracking and sharing information across companies…
You and I are in agreement. It's one of the reasons I think trying to break up Google is actually a terrible idea for the health of the Internet (in any frame of reference other than an anarchist "burn it to the ground" mentality).
I'm not defending it, but the win would be for website owners who might make slightly more profits, and advertisers who might pay slightly less for ads -- all because increased competition would reduce profits by ad exchanges.
Of course, that's against not just more tracking/sharing as you mention, but also probably significantly worse ad loading times and bloat in general.
It's awfully hard and hypothetical to estimate the impact of either.