Agreed. If nothing else, the boarding process is usually followed by an hour or more of mostly having to sit still in a seatbelt in an uncomfortably cramped airplane seat. Just sitting there in one place can be a painful and exhausting ordeal to elderly people with leg and/or hip problems, especially if it’s a several-hour flight.
It may seem absurd to us (temporarily) younger and healthier folks that anyone needs to conserve their energy and stamina in preparation for a long bout of sitting still, but that’s the lived reality of some elderly people.
My own late mother pretty much gave up flying after she had her hip replacements. She could still walk around just fine most of the time, and even push her shopping cart to the grocery store a mile away and back again, but sitting on the plane was a very unappealing prospect. Standing in long lines before getting on the plane would just have made it worse. Slowly walking to the exit after finally being able to get out of that damn airplane seat, on the other hand, would have been a comparative relief.