When the program aired originally, VH1/Viacom would have bought time-limited, media-specific licenses (i.e. you can play my song on cable tv on this program for 5 years if you give me $x dollars flat fee.)
If they wanted to release the thing again on a different medium (say internet streaming, or DVD) they’d need to find who owns the rights (it could have changed if the rights were bought or whole companies were bought or whatever) then they need to pay them all more money, for a DVD they could offer like .25 cents per $15 DVD sale or whatever, but for streaming that’s a monthly subscription so the royalties all need to be re-evaluated (for ad-supported)
Anyway, paying lawyers/accountants to sort it all out is an expense in and of itself, (in the like 10s of thousands of dollars range) for like maybe 100s or 1000s of dollars in revenue, and it just doesn’t pencil out.