At Wondercon, La-La Land was asked about older Universal scores and said that source tapes for 50's scores were hard to find, and sometimes incomplete when something was found. So I think a lack of sources is the biggest obstacle.
I mean the Rozsa Paramount scores were also hit or miss, with some scores only having two or three surviving cues. I’m glad that everything Rozsa that could be released from those vaults, was released from those vaults. I hope someone gives the Universal Golden Sage vaults, however spotty and incomplete, the same treatment.
Maybe LLL will dig-inn Universal if possible. I would definitely take Skinner in a set on day-1 - Naxos - Marco Polo Etc.. has bare-bones of Skinner i'm pleased what I got but hopefully more can be high-lighted - premiers would be swell.