Let's say they uploaded every single GN'R show available from 1987 to present monthly, for say, 9.99 a download at a minimum. That's a few hundred shows at 10 bucks a piece. Right there, with minimal effort in (restoration + uploading costs) they'd have a reoccurring source of income for at least a good few years to come.
On top of that, maybe every once in a while, do deluxe MP3/FLACs of "special" shows for example Ritz 1988 remastered audio with rehearsals that fans haven't heard. Charge extra.
Do singular releases for each of the albums NO BOXSETS for example UYI 1 + remixed or remastered versions of the songs, polished demos, unheard tracks, outtakes, alt cuts = $100. Fans would buy that if say you managed to cobble together 10-30 extra tracks. Plus do something like the Stones do and have Axl and Slash nowadays finish a UYI demo and release it as a 'new' song. Like the Stones did for Exile with 'Plundered My Soul'.
Not only that, but for a band that loves merch, why not re-release some geuninely fan favorite T-shirts EX UYI era t's? You could upsell these and hardcores would buy them if they're good re-prints, plus you'd be cutting into the market for the actual vintage t's which can get very expensive. The band wins by selling merch the fans actually want to buy, plus the band wins by selling merch that's popular to sell instead of toy trucks.
Then you could do misc stuff like other bands do such as more posters (of say current and past lineups). EX large size poster of the UYI booklet "Dead" photo. Or do a coffee table book of photos of the band from 1985 to present. HQ scanned pix of live pix, and then rare/unseen and candid pix of the band in all different eras. Make it a coffee table book with lush pictures, charge a $60-100 a piece. People'd buy that.
These are all simple ideas. Why do they seem so hard for GN'R?