Poor or non-existent wheelchair handling is extremely common and more so at major hubs where it is contracted out via the airport to a 'handling' agency. I have often seen pax in wheelchairs effectively dumped where they cannot see an information screen and edgy about whether they will be taken to their connecting flight. I think FedEx handles packages better. Ideally, wheelchair bound pax should have the same handling as children where they have a bar code/RFID that is read at each step. At least then a departure gate could see that the passenger they are due to get is in a wheelchair and at a remote arrival gate because nobody is bothered to get them to their connection. This failure to handle wheelchair bound pax has in my experience lead to delays in turnarounds due to no-one there to deplane them or board them, that have resulted in aircraft losing departure slots probably costing more for one flight than running a good system for handling disabled pax for the month.