This power transference issue is complicated though.
Morgoth empowered his minions to the point of diminishing himself. (Tolkien says, interestingly, that at the end of the First age he was less powerful than Sauron at the end of the Third).
Sauron did likewise, but to no loss as long as the Ring existed. Furthermore, for some reason, he is only strenghthened by its possession, as in some feedback loop. Maybe Morgoth was being too indiscriminate in his dissemination of his evil?
Then, there are the Valar' works (the Trees, the stars, dwarves (who, at their very beginnings, were perhaps no better than Aulë's own kind of will-less orcs), which didn't seem to impact them at all, eg. by making them lose the power of (re)incarnation that Morgoth and Sauron had lost. Or maybe it did, ultimately? The Valar ultimately did give up direct wordly intervention; I suppose I can fancy that a reason.
I expect that either Tolkien, Christopher, or members of some learned board have already addressed all this perfectly.