In the USA, gas taxes cover only a tiny fraction of damage to roadway. In Europe it heavily exceeds it, and most of Canada is about break-even. And that's of course ignoring that gas taxes are meant to not simply be user-fees for the roadway. Also ignoring costs outside of infrastructure - stuff like traffic enforcement and health costs. And it assumes the land the road was built on was free - which it obviously isn't, particularly in the kind of dense environments where road widening is impossible.
Yes, in the aggregate, gas taxes don't cover maintenance; but, as I said in points 1) and 2), the typical urban sedan driver is still overpaying since they cause virtually none of the maintenance costs (by percentage). (AIUI, any cab taxes exist to fund the regulatory costs, not the excess wear they're causing.)
Furthermore, the point under debate was whether Uber, as a cab[-like] service is underpaying for its road usage -- relative to the typical person -- by driving so much more; that point is still wrong because their per mile costs are unchanged with such higher usage.
