People would probably do more sustainable things if those things are made easier for them.

to put an example. Recycling not only requires space for different bins, but also know what goes into which one. The second part is where I struggle.

If government financed solar panels, people who has houses (opposed to flats) might find useful to install them to complement the electricity or fuel they use for their generators/consumption. Sure, maybe solar won't cover all your needs, but if it covers 20%, that is already 20% less in your electric bill (and 20% less contamination).

Walking might be nice if the streets are clean and accessible, but terrible if you walk at the side of a road and have to endure car's smoke.

We probably need to think ways so we can contaminate less but that aren't too burdensome. In my experience, pointing out that you can reduce your electric bill works better to encourage to waste less energy than talking about contamination. So let's focus on additional benefits for being sustainable. People want things to be "easy". XD