My DD has a big buggy - a wheel base with two tops: a carry cot/pram and a buggy/pushchair. The pram top was for when the baby was young, but as she grew, and liked to sit up and see the world, the buggy top was used. Either combo, with pram or pushchair top, is nothing like as big as the coach built prams we had for our children!
She is a single mum who doesn't drive, so she does a lot of walking with her baby and dog, frequently walking the two miles to our house. A small fold-up buggy, with flimsy plastic wheels, would last no time at all, and would be an uncomfortable ride for the baby on long walks. So she has no choice, really. She has to have a buggy that is strong, with suspension and large rubber tyred wheels, that will hopefully last the 2-3 years that she will need it. She cannot afford to keep replacing it.
And as she lives in a tiny house, where every inch of space is needed for the essentials of living, she quite literally does not have the room to keep an additional, lightweight buggy for bus journeys! And yes, she has been upset on more than one occasion when told there's no room for her buggy unless folded. Impossible to hold a wriggling 10 month old, and a heavy shopping bag, while trying to fold and manhandle a large buggy onto the bus - and there's never any move on the part of the driver to help her! So she knows that if the spaces for buggies are all taken, then there's nothing she can do but wait for the next bus. Sometimes in the pouring rain and with a baby who needs feeding, and a dog waiting at home that probably needs to go in the garden.
So I do have some sympathy for your neighbour's rant Grannyknot. It really isn't easy if you don't have a car these days.