My now adult daughter uses a wheelchair and I have said a number of times that we don't rely on airport assistance as it is simply dire. We bought a collapsible wheelchair that packs into a kit bag slightly larger than the hand luggage standard size to be independent of the assistance offered. Most crews kindly store it in a cupboard on board but it does occasionally get placed into the hold from the aircraft door.
On one such occasion it didn't manage to make it from the door to the hold and was left behind at our departure airport. On arrival at Heathrow they arranged a buggy for us. Familiar with the concept that a wheelchair user is generally allowed one assistant at most venues, and knowing that other hand luggage complicates the process so we keep it to minimum, my wife travelled with my daughter on the buggy and I walked with my two sons. She was astounded a) how whole groups of able bodied passengers insisted on travelling on buggies with the one passenger in their group requiring assistance when one person accompanying would have been plenty, and b) the amount of hand luggage the groups had with them that also had to be transported on the buggy.