Again, I feel like a lot of people over simplify and just go, "My gas is X, the train ticket is Y. X
I don’t think it is an oversimplification honestly. It might work out as a favorable arrangement if we’re only talking about only moving around within a larger city with robust infrastructure, but the scenario of the post with a 4 hour drive speaks to the fact that this isn’t the case.
For driving a fair distance your expenses will be gas, tolls, and parking generally. A long-range train ticket will likely cost more than all those combined and then on top of that you’ll still likely have to pay for extended parking and/or other transportation on one side of the trip if you don’t have someone you can rely on.
I don’t by any means live in the middle of nowhere and the nearest train station to me is still over a two and a half hour drive. I don’t enjoy it, but the infrastructure just isn’t there to make this a feasible option for many people.