People in North America don't realize how freeing it is not to have to own a car to do things but without adequate transportation they only see the inconvenience of not having one.
To an outsider (I lived in Grenoble before) it's so obvious that I joined some mobility associations as soon as I moved here, and I wasn't even politicized about this before, nor was I in any real sense active in the associative milieu.
I last owned a car in 2009. I lived on Long Island’s North Shore at the time. The public buses are not great (NiceBus), and the train not very convenient (OB branch). Still, there is as a train and bus service leaving town. There is also a nice in-town municipal bus that costs a dollar and goes to downtown and the grocery store. As it is, the store was only 1.5 miles from my house.
All of this is fine if you’re single. But if you have a family with all the shopping and taxing, it’s not very appealing.
I now live in Queens, NY. While the public transit is better. Unfortunately stores are more spread out and now I’m 2 miles from shopping and there is no shuttle.
All this to say—I’m living the dream without a car, and NYC, even out in the sticks, is not bad if you’re single.
So if you want to take a TGV to/from Paris, it is nice. Anything else, less so (try looking at fast train route from Lyon to Bordeaux - through Paris)
FWIW yes, TERs need much, much, much more love in France. Instead, the govt is still refusing to finance repairs to re-open e.g. the "massif central" line.