This is all probably for the best. Hear me out.
A remaster would be really nice. We'd have a fancy new title screen that lets you launch each game from it, 1080p/60fps and all DLC included. However, a remaster would still be three separate games.
The fact that it's not happening, paired with the fact that the original trilogy is so beloved by fans, means that people are not going to stop asking for it. If enough time passes, and the demand is still there, it might be worth remaking the trilogy. A project like this could even be outsourced and released in between or after the new Andromeda games to keep hype alive.
Imagine next-gen graphics (but all the same voice acting), unified (ME3) gameplay and RPG systems and not having to re-customize Shepard at the beginning of each game. It would probably be Game of the Forever.