There’s no reason. Really there isn’t. So many cult and genre films have special editions and new scans from boutique and even studio labels now that it’s ridiculous when classic titles cannot get the same treatment.

Almost any label would give anything to do a release. I’m sure if Arrow, Indicator, MOC or even Criterion made a deal for a limited print run that was only the theatrical editions it would sell out in a nanosecond and prove us right after all these years.

It’s just simply getting the powers that be convinced.

It could be as simple as this, particularly if the licensee wasn’t allowed to make new extras:

Brand new 4K or higher res scans without any monkey business and proper color grading. Now with 4K UHD there would also have to be a proper HDR grading pass as well.
Include all original theatrical audio mixes (35mm Dolby Stereo, Mono, 70mm Dolby Stereo. LFL has them all archived.) and the 85 and 93 home mixes most are used to. Leave the audio alone and do not subject the tracks to overzealous manipulation like remixing effects, de-noiseing, re-equalizing and nearfield remixing.
Properly encode the discs and max out the bitrate. This is important as a lot of discs usually don’t have good encodes.

That’s it. That’s all it takes. So really all it needs is the right person to say yes or care to even hear the pitch.

If it was Arrow or Indicator the boxset would have original art, every scrap of extras they could possibly get and be packed in a handsome slipbox like most of their sets at an affordable price. Arrow is now stepping into UHD so they could do it for both formats.

For example, the 1980 Flash Gordon (which I adore) is finally getting a new 4K restored transfer after years of the curummy old Blu-ray which made me always watch my Laserdisc copy instead. The full UK boxset release is 5 discs loaded with extras and a UHD version. All releases will have the original 2.0 Dolby Stereo and the 5.1 remix losslessly encoded. Arrow is doing a big SE release in the USA also in 4K UHD. This is because Studio Canal is doing catalog 4K restorations and actually releasing them to disc consistently unlike most. So now the film made because of SW’s success will have a better and more feature laden big release than the film that inspired it.