When I worked in Paris, I lived in the suburbs surrounding Paris and worked in another one.
Public transport was easily 1h30m of traveling time. I would have to go through the town center and back. Share the train with all the people with the flu, suffer the unpredictability of the Parisian public transport.
In my car, it was a solid 20 minutes, and I never caught the flu. I was saving 2 hours everyday thanks to my car.
I'm not saying it's perfect for everyone, but for some people, it's definitely really great. Would I ever take the public transport again? Probably, if there were better routes around, not like this though.