The relevant part of those examples was the fact that it is possible to disentangle pleasure from the desire to keep doing the pleasurable thing. Yes, we could upgrade ourselves to a posthuman state where we don't get tired after eating or sex, and want to keep doing it all the time. But it wouldn't be impossible to upgrade us to a state where pleasure and wanting to do something didn't correlate, either.

I believe the commonly used definition for 'wireheading' mainly centers around pleasure, but your question is also important.