Yes we do
As the song goes, "well I've never been to London ..." but I have used public transit in cities where I live and where I have traveled, with a child that uses a wheelchair. In several cases, conditions were not what was advertised. Like Katja says, wheelchair users of public transit are out there. They're in London too. I suspect there will only be more as the world becomes more universally accessible and people can count on getting where they are going after they get off the bus or train or plane.