It is an important distinction, though. Novak, Rafa, and Roger all pretty much went into a mode of prioritizing Slams on their schedule late in their careers - everything else seemed like a warm-up to them. It isn't that they didn't play all out in every tournament, but just that they shifted in terms of the weight of their priority. But that's not where I see Zverev at. The Big Three were wanting to add to their legacy, to enjoy "one more" Slam win, while Zverev has more of an edge of desperation.
And yes, it is an interpretation on my part of where i think Zverev's at mentally: deeply frustrated and only really caring about that Slam trophy. I think the term "consolation prize" suits how he must feel at the thought or reality of any other trophy at this point. I mean, the guy has even stated that he knows he's considered the best player never to win a Slam. I'm not even sure he'd be all that happy reaching #1 without winning a Slam; it might even add to the agony of that dubious label.
I agree with you that this is not how Zverev should approach the game. Slam titles, I think, come about through all the things that lead up to them - a rising tide that crests at the right time (or a sustained level of dominance that only the greats can really maintain, which puts them frequently in the position of the possibility of a Slam title). But I also empathize with the reality he's found himself in. I think his frustration and even desperation is understandable, and is borne out of feeling that he can't get better than what he's shown so far - he's optimized his game, at least at times, and still failed. Poor guy, really.