I don't think there are any good reasons. I'm sure there are enough masters (films etc...) to put a hand on these.

It's a little like the story of the "lost" master tapes from ESB falling in pieces (the 4-track sessions tapes) that make some around like SkyJedi -no harm meant- say that there's no hope to have better, wich I can't agree because... All the music is/must be still available through original 24-track tapes. The proof is that the last part of "Drawing the Battle Lines" was remixed from these for the SE whilst it's not on the original album. This one for other instance provides a bit from "Captives" (in "Betrayal at Bespin") wich is considered as an underscore part (usually underrated) at the end of "Departure Of Boba Fett".

Then I'm a little perplex when knowledgeable people come and say "the master tapes are lost" !

... Let me ask then: wich ones ???

'Hope this answers in a way.