I'm in favor of proportional fines based on income or assets for equitable deterrance, particularly for traffic-related violations. The only problem is that fines can only deter people with forfeitable  income or assets. Indigent offenders don't care if a fine is $1 or $1,000, it's not getting paid. Jail is the only threat, or at least the only way to incapacitate them from violating for a time. 

Probation's just a hall pass to re-offend until caught again. Rehab has to involve voluntariness to work, and requires support and accountability for the indigent during that period -and- they have to be willing to become productive citizens in terms of behavior and employment or they'll just be back on the streets offending.

We have to put money into supervised care for the mentally ill indigent, many of whom will not get better. We need to carefully design and fund programs for those willing to be saved from addiction. 

But we also need cells for the hardened remainder. That's reality.