My experience and observation say otherwise. I have no incentive not to litter when I know no one will fine me. Still I get up and walk trash to garbage cans. Even with all the litter around, most people still walk trash to garbage cans instead of littering.
Most people don't shoplift even when they know they wouldn't get caught. Most people stop at red lights in the middle of the night when no one is around. Etc. Etc.
I've found living by my values the greatest incentive. The alternative is to try to accept that my comfort and convenience come at the cost of others' health and resources, which ate me up inside.
I think most people value clean air and water enough that when the culture shifts, they won't need material incentive.
Laws will follow behavior, not the other way around.
It is also a question of habit and social norms. A lot of what we claim is internal moral values, is really just social conformism. We don't throw garbage around and shop lift in large part because we don't want to be worse people than everybody else we know.
We see this in countries with a lot of cheating on taxes. It is hard to break out of, because nobody wants to pay taxes while knowing that none of their friends pay. Nobody wants to be the lone sucker doing the good deed. On the flip side you don't want to cheat on taxes if you know everybody else is really particular about paying it.
So I think the establishment of social norms is very important. And to do that one might need to create incentives and rules to kickstart people. As the norms develop you could cut back on the incentives and rules.
I've seen this in my native Norway. Fathers and mothers could split the maternity leave. Although almost no father took advantage of this. It simply wasn't an established social pattern. Your boss would look funny at you if you did it. Then the government mandated that some weeks should be taken by the father otherwise those weeks were lost and could not be used by the mother.
Within few years the social norms around father staying home looking after kids, changed radically in Norway. Hence government policies DO matter for how personal values and behavior develops.
Beliefs like this are why I focus on leadership first. There are many examples where we choose difficult things because of the reward
- Sports and exercise
- Learning and personal growth
- Writing free software
- Having children
- Going to the moon
Many other examples. They generally turn out to have other benefits, but they are challenges. Yet we love them.
With all problematic behaviours, citizens fall into three groups: 1) those who refrain out of a healthy sense of personal responsibility; 3) those who persist out of a pathological understanding of personal freedom, and then 2) those who refrain only because they fear personal consequences (ostracism, fines, jail time).
My suspicion is that a well-written, well-hated law can push a healthy chunk of people from pompous group 3 into reluctant group 2. As the next generation sees less of the problematic behaviour growing up, group 3 shrinks smaller and smaller over time.
That's how progressives ended slavery, got women to vote, made gay marriage mainstream, banned public smoking, and how we are now reining in the war on drugs; it's not clear why it shouldn't work to address energy decadence and meat overconsumption.
"Get on board or we'll screw you over", which is exactly the dynamic a "well-hated" law creates, is not how a healthy society is run.
NY-SAFE is an example of a "well hated law". How is it working outside the areas that wanted it in the first place? Culture isn't shifting very much as far as I can tell.
Likewise in spending thousands to upgrade from an average 25 mpg car to a 35+ mpg car, only to drive down the road alongside coal-rolling semis that believe DEF is a conspiracy.
I'm really curious about this as well. I drive an old Honda Accord that gets ~22-26mpg. In Texas I can choose to only purchase renewable energy, but how much environmental impact will be had from my purchase from an electric car compared to keeping this nearly two-decade-old car running? What is the point where this car is better left as recycled metal vs. keeping it running?
- How much you have to drive. The more you drive, the more you can offset the embodied carbon footprint of the EV, and the more fossil fuels you offset.
- How fast your decades old ICE car deteriorates, and therefore decreases in efficiency and increases its operational pollution emissions.
- The embodied carbon footprint of the vehicle parts you replace through maintenance of an old vehicle.
High range EVs with large batteries cancel their embodied footprint in 18 months with a typical drive cycle, even lower if you are mostly using renewably sourced electricity. Lower range EVs take even less time 
It sounds to me like from your situation (old car, renewable power available) the numbers already suggest you should do it now. From the report linked below, driving an EV in Texas today is like getting 52 mpg with an ICE car. If you're using only renewables it is multiple times more efficient (see equivalents for CA and NY)