I'm so sorry that you had to go through this.
This happened to my grandmother, also a veteran, on a Delta flight to Atlanta last year. She requested a wheelchair, and got by just fine until she came home from Atlanta. The plane, for whatever reason, couldn't actually pull up to the terminal and they had to exit down the stairs and walk into the airport from outside the plane. Lucky for her she's able to walk short distances and the flight attendants helped her down the stairs. I can't imagine what it would have been like for anyone not able to walk.

You are absolutely correct in your last sentence, but I would expand that to all airlines.