@michiel Sure, everything is just a matter of effort/money. They did it once, they can do it again. The difference is that TNG didn't use the VideoToaster until Season 7, everything before then was lots of practical effects and only a touch of VFX, maybe not even digital, for e.g. phaser fire.
For VOY and DS9 I assume all ships and stations are digital effects and reproducing an episode could mean a significant portion of the original cost for the episode.
Would enough people shell out for a remastered Bluray box that was more expensive than the TNG box? Would enough additional people subscribe to P+ or rewatch episodes on Netflix in non-P+ regions for an enhanced DS9? Lots of fans will stream the episode whether it's enhanced or not.
These people erase whole series from their catalog, already produced series, for underperforming. I don't know that they can be convinced they could earn that money back. 😔