Fines unfairly affect the poor. The punishment should be community service, say highway trash pickup.
Getting screwed out of 4-8hr of your time is much less likely to make your standard of living and financial stability slide backwards in a way that takes many months to a year to correct. Of course the majority of support for people who are in favor of anything other than the status quo comes from people who want petty stuff to be maximally life-interrupting so....
All I'm saying is it's not clear-cut that community service is less disruptive to the poor than a fine. Maybe the fine should be a percentage of your income instead of a fixed number, as is done in some places.
I can see your point, so instead of increasing the fine for texting, I would be fine with losing your license permanently if you are using a phone while driving (talking or texting) and are at fault (any percentage) in an accident.
Would disproportionately affect rich people living in suburbs.
I.e. the people who are financially secure enough to have spare fucks to give about matters of principal rather than economic survival.
Legislatures that want to get reelected can't just screw those people. It's a long slow process of divide and conqueror and pulling that off assumed continued political will.
Almost any penalty one can come up with will be harder for the already-disadvantaged, and still shrugged off by someone with sufficient resources.