The Mortality of Elros

[Numenorean]

Lord Elrond:

I don't think there is any in depth reason why however if I were to make believe I will say that he was a daddy's boy and wanted to be just like his father who was mortal.

Elros' father was half mortal and half Noldor, his paternal grandfather, Tuor, was entirely mortal, at least to begin with.
I disagree Elrond, and think that some seriously deep reasoning was behind Elros' decision to choose mortality, certainly there was more to it than the 'daddy's boy' theory.
Maybe he saw that Men were leaderless after Morgoths defeat, and as he was probably one of the only remaining direct decendants of the ruling House of Hador, it was therefore his birthright to rule the remnant of the Edain as a mortal.