Valve is obviously right. You don't own any games sold to you. You don't own any commercial, proprietary software sold to you. On only have ever been a license holder. You own that license but are restricted by the license. IE. the same thing that keeps from from making copies and selling them is used to let them shut down the required servers whenever it stops being profitable.
If you don't like this then stop using proprietary software.
If you consider that owning it then you must not have a problem with Assassin's Creed servers going offline. You are saying you own it even with restrictions. If you accept limited ownership of software then you don't get to decide on those limits as a consumer. There are other examples of limited ownership (eg. animals), so I'm not going to try to dispute the terminology. I personally don't consider the idea of limited ownership of being of much use when dealing with copyright abuse.
You were previously talking about licences and ownership of "any games". What you mentioned now is an orthogonal concept, and affects a subset of all games sold.
Some aspects of the license covers "any games"... like not being able to sell copies. Some only impact games with an online component, like AC here. All these restrictions come from the license agreement you buy.
You're purchased "good" was a license to use some software. That license defines the rules for using that software. If the license says they can remotely disable your game then they can remotely disable your game without violating the license or committing fraud.
There is of course some question about the enforcement of licenses, particularly click through licenses, but the legal doubt doesn't help due to the arbitration clauses in those same licenses and/or challenging them in court being ridiculously expensive.
Nope. They are the same in this regard. You don't own it. Not as obvious with most cars today but it is starting to become so with some new cars coming with software subscriptions. Though really if you think about what it takes to repair a car you already see that you don't own it. It takes tools that the manufacturer sells to interact with the software, and no specs/documents on how that works either. Black boxes all the way down.
If you don't like this then stop using proprietary software.