@Techaltar we have Simple in Hungary (you may actually know of it) as a payment app, can buy transport tickets both in Budapest and nationwide, parking tickets, cinema (non-chain ones) and motorway vignettes
but i feel that this needs services that are unified (e. g. nationwide buses with Volánbusz, trains with MÁV, Budapest transport with BKK), and in the US, this oftentimes isn't the case, i presume