If the RAF changed and accepted NCO pilots, all they will achieve is a greater outflow of trained pilots to the airline companies.
How could they justify the different pay scales, as NCO pilots would have to be paid less the the officer equivalent, and I cannot see them accepting that situation for more months than is necessary, so to protect the airline jobs for the officer corps, NCO pilots is a non starter.
Besides, NCO's make better engineers than the officers, so lets keep the best guys for maintenance. (well you can train a monkey to ride a bike, but can it fix it!)