It certainly makes sense to spend on different things depending on your wealth. But I think people already do this, intuitively. I'm sure they generally don't do it optimally but it doesn't look to me as if the main problem here is failure to react correctly to change in wealth; I think it's just that most people do a very poor job of choosing what to spend how much on.

Suppose you expect your wealth to change enough in the foreseeable future to make a big difference to how much you should spend on what. Well, then you're anticipating either a large rapid change in wealth or slower change plus a substantial time lapse. Those are both things that I would expect might affect my preferences in ways I can't necessarily predict accurately. So rather than "wealth triggers" I would suggest sitting down once a year and shortly after any big sudden wealth change, estimating your assets and likely future income, and reviewing your spending in the light of that.

What's the value in discussing specific numeric thresholds? As the last paragraph indicates, any given person's optimal spending patterns will depend on their preferences, which may differ a lot between people (as well as between different temporal instances of "the same" person, which was my point above).