I think it’s less a feature of the English language and more a difference in the culture. If we’re brought up hearing that people are either friends or they’re not (i.e., we never hear people referred to as “acquaintances”), then of course the meaning of the word “friend” is going to become diluted.

A hundred years ago, it was far more common to refer to specific people as acquaintances. Now, everybody is a friend or a co-worker (a dry, dead word that holds no humanity).