Why don't we have better lenses?

Question 1:

Vivitar/Rokinon/Bower/Samyang/etc. off-brand 85mm f/1.4 lens: $280. Manual focus only. By all reviews, very good reviews optically.

AF versions:

Sigma: $1000
Nikon: $1230
Sony/Zeiss: $1700
Nikon G: $1700
Canon f/1.2: > $2000

An AF mechanism costs less than $100 (or $100 lenses have one). Vivitar makes autofocus lenses. Why don't we see cheap, fast off-brand (or even brand-name) AF lenses?

Question 2:

You see a ton of C-mount f/1.8 zooms (or even faster). Why doesn't someone scale those up a bit, and make an f/1.8 zoom for APS-C? Heck, some of them work on u4/3. Why don't we see those, just retrofitted with AF?