"To men He gave strange powers"

While I was listening to my tape set of the Silmarillion (again) I noticed for the first time the idea that Morgoth kind of had to "spend" his power in middle-earth and go he's keeps getting personally weaker as he goes along, even though he keeps getting more Orcs, Balrogs, etc. It would seem like Sauron as a Maia is like Morgoth (Melkor) the Valar in that he has a finite amount of power to be dispersed. So Sauron giving out the rings to the nine is a way to make a divestment into a good investment. He might put a dab of power into each but as a return he gets his most powerful slaves. The elves have this finite power, too, it would seem. They end up becoming intensely weary of Middle-earth - Galadriel talks about how she will diminish and what happens to Arwen at the end of her life is like an intensely sad fading into non-existence. The power that is given men, however, is different in that although they are weaker than elves, they consistently reach beyond their own natural strength. It is like men are here on borrowed power, or borrowed time to use the common phrase. The elves have a hard time understanding men because men's souls belong to another realm. Men are shown to do the "impossible": Beren, Earendil, even Turin although his story is a tragedy. In the later days of Numenor, the downfall of man is that they do not accept their dignity as those who can die and go to another place prepared for them but as yet unknown. But that is another whole subject; I don't know what Merlinus thinks about all these ideas - maybe he'll set me straight and enlighten us....