If you are convicted of vehicular manslaughter, you are very likely going to serve time.

However, if you hit and kill and cyclist in the US, you are not likely to be charged with vehicular manslaughter, so long as you were sober and weren’t actively trying to hit them.

Whatever laws are on the books are virtually never actually enforced against motorists, because motorism (and disdain/resentment against cyclists) is deeply embedded in the culture.

The default reaction of the median American (or at least, the median law enforcer) to any accident involving a motorist and a cyclist, regardless of actual fault, is “fucking bikers always breaking laws, running red lights and stop signs, if they want to take our lanes and slow us down, why don’t they think they have to follow rules like a REAL vehicle,” etc.

A joke I heard a few times was "If a bike fell out of the air onto a parked car, the car owner is going to court."

Certainly the perception is that drivers don’t face jail time in such a situation.

No. It will be slap on the wrist time if there are any consequences at all. All it requires is a driver to lie about some mitigating cause they weren't responsible for.