For the rest of us the roads provide access to our needs in one fashion or another even if you do not drive -- the bus, taxi, friend, Uber, ambulance, fire truck, police car, USPS, UPS, Fedex, oil delivery, meter-reader, etc., providing goods and services to you do use the road -- so it is proper that everyone pay for it
However, the same is not true of public transportation
Stop. Right. There.
You just conceded that Property Tax Payor's interest is the promotion of general mobility (because it increases the access afforded by their location, location, location)
These Payors want/need the most mobility for their public-street-buck, even when they don't have a particular stake in any particular vehicle or particular trip. They want maximum economic activity per lane-mile-hour, and they want all the activity buzzing around their property to raise its value. Foot traffic for retail, easy commutes for offices, easy movement of freight for commercial/industrial.
The property owner has an interest in MOBILITY which is NOT an interest in car-movement. In fact, general mobility is often diametrically opposed to cars. Sure, in Lexington mobility==cars, but elsewhere cars==congestion. Because they so freely "move in" and we don't have congestion pricing, they're really good at converting a public good (road space) for their personal use/enjoyment in a way that other modes don't.
people in cars squat on/privatize a whole lot of square feet of "public" (property-tax funded) asphalt (even when parked), and even more square feet maintaining a 1-SOV-behind-another "safe following distance"
and do so for many lane-mile-hours, often at prime times of day, all to facilitate just one fairly-low-value trip.
Instead of facilitating economic transactions, cars congest it and bog it down to benefit just a few drivers (compared to how many people's packages can ride on a UPS truck or how many can fit on a bus or trolley).
Property-tax-payers (particularly in MBTA Zone 1A) need/want to be promoting general mobility with their money, not car mobility. Car mobility turns too much of the generally available good of the public street into a big expensive bubble for just one car which then pounds away until the potholes happen.
Property Tax Payors get the most for their streets when mobility per lane-mile-hour and activity-per-ashpalt-wear is maximized something like this:
QED: Subsidizing transit (and complete streets) is the more cost-effective way for property owners to maximize the mobility that serves their property; yielding superior returns compared to encouraging/subsidizing/underpricing/letting cars congest up those streets, scare off the foot traffic, bog down uber/taxi/tourists, and bog down their packages/deliveries/freight.