Conventions exist in every language. `car', `cons', and `cdr' are also part of certain standards (e.g. RnRS). And, honestly, they compose a bit better than `first', and `rest' for combinations like `caddr' and `caaddr'. I suspect that you're going to be even more unhappy with those constructions.
The same can be said about older languages like C, which also have standardized notations.
Because it is broken. It's not broken if you've already learned it and internalized the terminology; it's broken for everyone else because it's needlessly difficult to learn (and actively dissuades people from wanting to learn it, hence all the articles evangelizing Lisp).
By that rationale every foreign language is broken, and, maybe more pointedly, every language but Chinese (or possibly Spanish) is broken and needlessly difficult to learn.
The trend of history since babel seems to be going in this direction. If there is eventually a universal common tongue this rational will be proven right.
The same can be said about older languages like C, which also have standardized notations.
Why fix what isn't broken?