Most people need cars may be true now, but it's not a law of nature. These things affect each other. The village I was raised has about 8000 inhabitants. That sounds like sparsely populated and indeed, it has no good public transport connection - the closest light rail station is 5 km and there's no bus. But within a 10 km circle, you'll find 14 towns and villages, with a combined citizenship of ~60 000 people. And within 20 km, you'll find 6 actual cites with a combined citizenship of > 500 000 people.

You could run an actual public transport network there. But outside the cities and some light rail, it doesn't really exist - there's just a few bus lines that run every hour or so. Why? Because people have cars. When they tried to set up a bus line for that 5km to the light rail (which runs every 15 minutes, until late night), nobody would take it. People took the cars because they were used to it and didn't want to rely on public transport - especially since that was explicitly branded as "trial" - why change habits? And now, that bus no longer runs and people have to take the car.

Public transport thrives of network effects, but these are hard to establish. I believe it can be done, but only if you have an actual plan and the will to pull it through. It's a marathon, not a sprint as they always say.

If you're getting into regions where public transport is really hard to provide, then you're very quickly away from "most people need cars", because these regions may be large, but very few people actually live there. Let them use cars. Go for the large chunk that should not need cars.