I can't speak for the OP but I could've just as easily written the same thing that the OP wrote as I've seen the same thing in PHX. My point would simply be just an observation and curious to see what others have seen in terms of the number of wheelchairs needed for any given flight. I would also point out that when you're waiting for boarding to start and you see the number of people that need assistance, you mentally calculate how much extra time is going to be needed and how late your flight is going to depart. Nothing bad about that, just that you know it will leave late. You then have that mindset when all of a sudden some/all of those folks get up and board themselves and now your flight is back on-time. It's almost somewhat of a surreal experience to suddenly see a dozen or so people who appear to need wheelchair assistance suddenly get up and walk. I'm glad that they are healthy enough to do that and at the same time would be very understanding if they did need the assistance I thought they needed.