As the others said, nobody pays for all of their impact or demand for the roads. In the case of transit, the cost of labor is the overwhelming chunk of expense. Transit is generally required to get at least 20% of the operating cost from fares in order to get any subsidies, but there are always some fiddles. And the transit agencies that were more fare-dependent before Covid (BART, Caltrain and other commuter train lines, GGT) also were harder-hit by the sudden loss of ridership and had to make bigger cuts to service.

As for other stuff, yes, we make the decision (not always conscious) to subsidize most travel modes from general taxes. Trucking is a large recipient of those subsidies, since their registration and fuel tax receipts don't come near covering the cost of maintaining roads for them. Light-duty probably roughly breaks even or is only a little subsidized - certainly, a lot less per mile than trucks. There are several ways a VMT tax could be figured that would match what light-duty pays now. And that basically covers just maintenance of what we have. Building new roads, like building new transit lines and buying new equipment, is largely covered out of general taxes not "road taxes."

A vehicle that gets 25 mpg average (fairly typical for mid-market CUVs and SUVs that aren't hybrids) and pays $0.50/gallon in fuel taxes (California's current gas tax, in round numbers; it changes every year) about $0.02/mile now. That's about the same as an EV that pays the annual $100 minimum surcharge and drives 5K miles, regardless of what it weighs or how much power it uses (EV consumption in the current market ranges from around 2.5 to just short of 5 miles/kwh).