The downfall of the hobbit-folk

[Thinlómien]

Originally Posted by Farael

Yet why would a people so hardy when pressed, so entrenched with all the forces of life become a shadow of their former self and finally disappear for all intents and purposes?

Even the hardiest can not endure everything.

I would add one more theory to why hobbits were lost. Maybe the Shire became unfertile and the hobbits either wandered away or perished in famine. Maybe Saruman's work had marred Shire too deeply. Or maybe the hobbits used the land too much. Or maybe there was a natural disaster.