One of the good things about the Museum Registration / Accreditation process is that to be part of the system a Museum has to have an acceptable Collection & Disposal Policy.
Yes there was a phase of ‘grab anything’ and that helped a lot of items survive but the latest accepted collection & disposal standards are far more onerous and I believe that you will see more considered acquisitions and possible disposals in the future.
Remember, without being Registered or Accredited it is unlikely that you’ll secure any funding for any major capital projects – especially those aimed at getting airframes inside.