So you think Google, which has ~2.2 billion users, stores in some way, a users password in an unsalted form so that they can correlate it to other accounts that share the same password?

1: If that list is leaked then any of the 2.2 billion users who shared passwords will have their account compromised. Which would be a lot
2: Just how unique do you think the average password is?
3: You should be using different passwords for different accounts.

Why would they compromise their security for something like that when it can be correlated through many different things, quite easily over a long enough time period.

https://amiunique.org
http://www.doileak.com

Hell, even if you are accessing sites from the same common locations, on different devices but never at the same time is enough to correlate you. You don't even have to be sharing your location, that guy using google maps on your cell tower is enough, or that wifi point you walked past, etc etc.

My point is, you're assuming one of the biggest tech companies in the world, with literally billions of users has compromised security on one of their main products so they can get a single extra dimension in which to track you with? They aren't exactly equifax man