Do you switch IPs, browsers, computers, etc every time you close the tab too? If not, Google tracks you.

Even if you did all that Google will track you. Whether they match up all your identities or not is another story.

Bring a laptop from your home back to your folks place and I bet they can make the connection...

No doubt whatsoever. A lot of those "Facebook is listening to my conversation" claims come from the fact that they'll associate people based on network locations, IPs, etc.

For example: You're at your friends house with the Facebook app, your friend clicks on an ad for socks. The next day you start seeing ads for socks despite not having any sock-related activity. This is just an oversimplified example.

Google has more than cookies deployed to get after you.

There are a myriad number of tracking vectors they can use. (And to be fair, so can any of the other companies out there tracking everything.)

Deleting cookies is certainly a start, but it's not sufficient to maintain privacy.

i know there's a bunch of ways to track people without cookies (supercookies, browser fingerprinting, etc.), but is there any evidence that they're being deployed by google or any of the big western advertising companies?

I can say for certain that I worked for a company that wasn't Google and employed plenty of ways to track people that didn't involve cookies.

We used it mostly to try and track malicious users (banned users, etc.) but it's still tracking nonetheless. It was reasonably effective.

I'm sure a company of Google's size and sophistication has many more advanced methods than we did.

Nobody is questioning their ability. It’s their willingness that’s relevant, and considering they are liable for a far more damaging PR nightmare than almost any other company, it’s not out of the question that they might not actually use every trick in their arsenal.