So? What does termination of radar services have to do with whether you fly a missed approach? Radar services are terminated explicitly in many situations on an approach when using a SIAP. The only thing that AIM quote is telling you is that ATC doesn't have to say the words "radar services terminated" for them to be terminated on a visual when you leave the frequency that is providing radar services (which seems pretty obvious anyway).

Termination of radar services does not mean cancellation of IFR.

Aside from that, let's try a scenario: You accept a visual approach in marginal conditions (why could be it's own thread but it's pretty much a given for this one). The airport is in the boonies, non-towered, well below radar coverage, and even below communications coverage.

Are you saying that the AIM is telling us to flounder around in the clouds until we make contact with a Center frequency rather than follow the missed approach for the runway we were going to land visually on?

I think rickair is exactly right on the options available.