Of course it has to do with antitrust.

In an America with robust, sane antitrust, first of all, a company as big as Nvidia probably never exists in the first place. Second of all, if it does, an "acquihire" like this will have to pass regulatory muster, regardless of whether it's a full-on corporate acquisition.

Because in an America with robust, sane antitrust, if a company as big as Nvidia does exist, it is operating under fairly tight strictures as a company with heavy market dominance. It does not get to just act like any other company.

That's what antitrust law is for.