Yes, you can make that argument against any public service. And it is worth discussing for any public service. All public services have benefits, and all of them are capable of being overprovisioned.
In the context of schools, literally everybody benefits from population wide literacy and education. The benefits are diffuse enough that it is worth subsidizing...although we're probably hitting diminishing returns on the amount that we do spend. And the idea that we need to learn russian if we don't have a military 10x bigger than the rest of the world is a cold war rhetorical relic. Of course we could do with less military funding.
Cars though, are mostly a benefit to the occupant, and either a detriment to everybody around them, or entirely capable of being priced into the benefit of the goods they buy. Yes, I can afford paying $0.0025 more for a pound of apples if it means the trucking company pays their true costs. And why should we subsidize your drive in a BMW to your office when you can easily pay for the whole cost yourself, or take transit? Why should we be subsidizing cars over the much more efficient alternatives?
Cars and transit are competing forms of transportation...a vehicle mile not traveled is very often a fare paid. Car costs scale linearly with the number of people-miles driven, until congestion and space constraints hit and then costs scale exponentially. Transit costs are step fixed costs, and therefore the more riders the less they cost per person. When we subsidize car travel, it forces us to subsidize transit travel even more, because taking away riders makes transit less efficient. It should be remembered that before we started price capping transit companies and subsidizing roads, transit was one of the most profitable industries in the world. That's the power of the cost efficiency of transit.
So yes, mobility is important and roads shouldn't just go away, but the amount of roads and car infrastructure that we fund through general taxes is absolutely obscene and should be scaled back dramatically. Mobility can be much more efficiently provisioned to the public with transit.