> When we arbitrarily pick one

Aren't all modes of transportation in the US either subsidized or public-owned to some degree? We haven't arbitrarily picked one; we picked them all.

Air travel is maybe the least subsidized, though? Essential Air Service is probably the main thing? Long-distance bus like Greyhound is only minimally subsidized too.

But local transit (bus & rail), and regional and long-distance rail are all subsidized or publicly owned in the US. Most roads are publicly-owned, either locally or by the federal government. Long-distance bus and rail are actually unusual in how little they're subsidized.