Do they need to own the apparatus? I search for a product on Google, I click on a search result, navigating to a retailer's site. That site knows not only what I'm looking at but what I was searching for. By way of third party cookies it knows who I am and it sends that info back to FB and the next time I'm on Instagram I'm getting ads from that category. The retailer I visited didn't have to own the FB ad network to play a role.
I don't think valve does any of that, and even if it did it has access to way less data then FB (which owns instagram and whatsapp) which basically know your location, who you talk to and when, your centers of interest, political orientation, &c. Valve, at least for now, is mostly concerned about selling games. Collecting data in itself isn't bad, imho the issue is the centralisation and what the data is used for. I'd feel much more confident giving a little data to Valve than enlarging the humongous dataset of facebook.
I think you’re saying that Google sends the search terms to the site you visit? It doesn’t do that, at least not for a bunch of years now. As a site owner you can get aggregate ideas of what queries lead people to particular pages, but you can’t tie it to individual visitors.
Every company that has your data will either sell it or else they're in enough verticals that it makes more sense for them to monetize it internally. It amounts to the same thing.
No surprise really but it irks me as I wanted the rift some time ago but then Facebook bought it.
Luckily it seems like Valve Index will be a good alternative.