Although elvish birthrates appear low, inter-marriage with men should also be considered. It is possible that children of such a union were no longer given the choice of Elf or Man, but would be Man. A low birth rate combined with inter-marriage would mean elvish numbers would continue to decline at a greater rate.

As the numbers of Man continued to grow, they would encroach on lands controled by Elves. While there may have been initial coexistence,at some point the elves would have to decide either to abandon their lands, or to fight for them. No doubt some would decide to fight. Some would move to more remote locations.

We should also remember that not all men would look on Elves with friendhip or kindness. Elves may have come to be blamed for some, if not all, of troubles suffered during the Third and Second Ages. Old hatreds against Elves, especially by peoples long under the influence of Sauron, would no doubt have continued. The notion that "the only good elf is a dead elf" may have been become more prevalent than we want to believe.

In the end, elves would cease to be real historical beings and would become creatures of myth and legend.