Your argument has no logical congruity. Trams are not available for me to use, because they are not nearby, and don't go where I want them to go. Roads are not safe for me to use as a cyclist. But we should fund public transport, and roads, because they contribute towards making a place suitable for business use, to promote an increased local economy, and enhanced standard of living for people who don't use those things, but do benefit from the wider infrastructure and social capital that they help support.
If you were to make an argument based on utility, you would perhaps need to get Guru involved to make a formula that looked at the ability of a subsidised transport method to carry people and goods, versus the cost of impact in congestion and consumption of resources (footprint on highways, wear on roads, consumption of land to store while unused). I'm willing to bet that cars are significantly over-subsidised and small personal transport massively under-subsidised (and increasingly necessary because public transport does not cut the mustard). Charging batteries, or burning fossil fuel, to move a ton of metal, rather than 20 kilos of scooter is surely a cost and environmental benefit that even the most dense can see the use of? All should play a part in an integrated transport policy, to assist in moving goods and people, in the most resource efficient way, which we don't have. If a thousand people journey to work every day on scooters, that's a thousand less cars, at a substantially lower cost in terms of resource consumption and frees those resources for other commercial and social activity, at a reduced economic, environmental, and resource cost.
It also means more staff can get to work because they are not being fucked up by public transport on congested roads, and thus be more productive working units. It also increases consumers flexibility in visiting market centres, and the possibility of them being more useful consuming units.
Use your car, or use public transport, but we are going to fuck up your public transport, only ends one way. Really badly. As times change, utilising new efficient forms of public transport should be increasing in importance, not subject to out of date dogma. There are all ready lots of places where the car is completely useless for certain necessary journeys. Freeing up road space by replacing many journeys with compact personal transport solutions is a positive contributor in this space. Using such solutions to hook up with existing transport hubs, when many people live and work in locations disconnected from them, could massively reduce the number of road miles consumed unnecessarily by large vehicles, unsuited for individual transport, in congested areas.
That is all a positive for an enhanced standard of living directly, and building a more commercially active market centre leading to increased wealth and a subsequent indirect increase in the standard of living. More than subsidising amazon to keep more profits, and pay their staff a wage below the cost of living, and consume the resources provided by society (roads, workforce), and not pay tax, does.