One person on a random fourm stated that...
That person sounds like a real authority on all matters.
But yes, what they said is exactly true, the TNG era series were edited on video because it saved time and money to editing it on film. It's not impossible to remaster the shows, it would just take a hell of a lot of work and might not make a return on the investment. There's a small chance they'll risk it for TNG since it was the most successful Trek series in terms of mass appeal, but DS9 and Voyager will probably never see the light of day on blu-ray.