I worked at a Florida airport for a short time and the wheelchair service is provided by a private company, not the airline. I have seen there been a few times that there would be multiple flights landing and there not being enough of those wheelchair folks to quickly service every flight. There were many times when luggage for a wheelchair passenger takes a long time to get the carousel and that further delays the service to get to another passenger.

Unfortunately, at least at the airport I worked at, it was a minimal wage job and they make their money on tips so it is hard to hire and retain employees plus the workload will vary every day so scheduling is a hit or miss.

Based on the experience I had working with the people that worked as wheelchair aids, they were all great people who truly enjoyed helping their clients to the point of waiting with their client when the family member was running late to pick them up curbside.