Lucky I'm in the UK, and buses here have 2-3 wheelchair/pushchair spaces. I can't drive so am entirely reliant on public transport. Banning strollers would seriously limit my ability to get around as I have a 3 year old who would struggle to walk the distances required when the 10 month old is in the pram. (I appreciate that it was a lifestyle choice to have two so close and it is not anyone else's problem). Taxi's would not be an option as a short 5 min journey costs more than 3 times as much as a return bus journey.
Twice a week I know I'll be travelling at rush hour so take Tadpole in a chest carrier. At other times or when I have to travel with both boys I will use a pushchair, it does fold however if there is space I will keep it set up, in the event of sharp breaking or Ana accident I would be unable to hold a baby safely in my lap and stop a three year old flying out of the seat.
However I will always seat Froglet on my lap at busier times, so an extra seat is available, when on my own, or if I have Tadploe in the carrier I will always give up my seat. I have on several occasions gotten off a stop early and walked a little further when another stroller or wheelchair user needs to get on at the earlier stop, to make the space for them (its outside a school, park and a leasure center, so is a popular stop for strollers & wheelchairs)gra I've also found that when I've had to fold the pushchair, someone normally grabs the baby or bags or stroller to help, I don't expect it but do appreciate it.
I hope that by being polite and considerate to others I build good bus karma for those time when I am unfortunatly an inconvenience.