I feel like I'm an expert on these threads because when I'm out with my 4 children we have a wheelchair and a big buggy with us. I also used to have a SN buggy for DS2. Not a maclaren major, a massive tank like thing that took DH both hands and a lot of swearing to fold it up to get it in the car. I couldn't have folded it to get on the bus but the bus drivers wouldn't treat it as a wheelchair and nor would the school when they said no buggies were allowed in the school building. Round here there are signs saying that wheelchair users take priority over buses but they aren't enforced. I hate that.
However people have buggies that aren't easily foldable aren't all idiots. If I just had DS3 in the buggy and my handbag I could fold it fine. One hand holding DS3 in a vice like grip (he is a bolter) and one hand to fold the buggy. But when I've got DS4 as well... DS4 is disabled and at 6 months has hardly any head control. He also gets cold really easily and sometimes overheats so I've got the footmuff on the buggy and extra blankets in the basket. I have to empty the basket of blankets, changing bag, prescription formula etc. Then get DS3 and DS4 out. By this point I've run out of hands unless I've got the older 2 with me. If I've got the older 2 with me I can put DS2 on the bus seat and strap DS3 in the wheelchair. I can tell DS1 to sit next to DS2 and plonk DS4 in his lap, while saying mind his head every 30 seconds. Then I have 2 hands free to take DS4's seat off, fold the buggy, gather up all our stuff and put the whole lot in the luggage rack. I have a phil and teds buggy. I have a mild disability myself (dyspraxia) and when I was pregnant with DS2 we did a lot of research to find the most suitable buggy for me to manage on buses and walking. There are lighter double buggies that are easier to fold but they are side by side or longer and I can't push them, not in a straight line anyway!
Obviously I don't do this, I just wait for a bus we can all get on without folding the buggy (often means it takes us ages to get anywhere, school run takes DH 10-15 mins in the car but takes me about 2 hours on the bus). But threads which patronize parents with big buggies annoy me. Because some of us have reasons for having a big buggy, we didn't buy ours because we wanted pretty accessories.