Yeah, I definitely feel the force of anti-replacement concerns, even within the scope of the objectively valuable. But I think they are clearest *pre*-replacement: given my current attachments, I wouldn't want to undergo a relationship-swap, even if it involved rewiring my brain to love my new partner just as much. I think that's just part of what it is to have genuine attachments (see also G.A. Cohen on "cherishing" values: philosophyetc.net/2008/… ).

The trickier question is whether the reasons for opposition persist even post-replacement. It's not so clear that they do. We do not have to (overall) regret that we grew out of our childhood desire to be a firefighter, for example. We may reasonably be glad that a past relationship ended, so as to make possible the one we value now. And so on. It seems like there can be a genuine conflict of normative perspectives across time, in these sorts of cases. I'm not sure that this can really be avoided.

An advantage of objective value here is that it at least blocks the more extreme problematic arguments, "like how we should try not to value anything because once you don't value anything you won't care that you don't value it." That sort of reasoning presupposes an extreme form of subjectivism. A more objective account of well-being can easily avoid that extreme end of the "spectrum" (as you put it). Objectivist views may (at worst) offer *retrospective* approval of the replacement of one objective good with another. That doesn't seem *so* problematic to me; partly, I guess, because I don't see what systematic principles would avoid this without having even more absurd implications (e.g. that we all must deeply regret not marrying our first crush).