On the positive side. Last year my wife and I flew to Australia (via Bangkok) with that well known Aussie airline. My wife suffers from MS and would need wheelchair assistance for the long distances from check-in to gate. Our travel agent was advised accordingly. On arrival at LHR a wheelchair was waiting, with a BA "pusher". We were whisked through check-in and assisted all the way to the a/c. At Bangkok, where a 2 hour stop was scheduled, again a wheelchair was waiting for us at the a/c. Ditto at Sydney.
In Oz we hired one of those electric buggies and via surface transport ended up in Melbourne before flying back to Sydney. Quantas, bless their little kangaroo, carried the buggy free of charge, and they ain't light! The same service with the wheelchairs materialised on the return journey to LHR. Top marks to Qantas and BA for the service.
Obviously you get the service you pay for and I would not expect similar treatment from a budget airline but I would at least expect a wheelchair - good grief even shopping malls and large DIY stores provide them nowadays.