It's true that user fees - gas taxes and tolls - for motor vehicle drivers in the US pay far less than the costs of the roads they use. I think it's roughly 50%.
However, assuming that by "electrification of mobility" you mean "everybody who's driving their own car keeps driving their own car, only it's electric rather than gas-powered", then I believe you're looking at it all wrong. In cities where people increasingly live, single-person cars have huge negative externalities aside from fossil fuel consumption, starting with congestion and moving on to over-building of parking, road deaths, sprawl, etc. Electric cars won't solve all of these, and neither will self-driving cars, or self-driving electric cars.
Instead, what we need for mobility in cities is better land use, with dense areas or corridors, safe walking and bicycling infrastructure, frequent and convenient mass transit, and congestion charging.
Do all that and you'll have real mobility fixes.