Because there is no concensus beyond genre, it becomes far too subjective. There are people who just won't consider a sci-fi or fantasy movie an overall GOAT because it isn't realistic. So about the greatest concensus you'll ever reach is that it's a great movie in its genre, and can therefore be considered a greatest movie period by those who most appreciate that genre. I'm sure there are people who consider T2 the greatest movie of all time. There are many movies who can't claim anyone as a fan of that level. But it's not going to be many people's GoaT.

Yes but not everyone likes action so not everyone is going to consider an action/sci-fi movie to be the greatest movie of all time, only action/sci-fi enjoyers will. Apparently Titanic is considered one of the best romances of all time but I won't personally enjoy it because I don't typically like romances

But because it’s not a biopic or period drama it misses out on tags like drama, story, biopic, thriller, mystery, horror Although it has many elements within the movie which make it an accomplished cinematic experience; I doubt most critics and fans could every truly clear the movie out of action sci-Fi territory.. Although to many it is so much more than an Arnie action flick

How many movies that are considered some of the greatest of all time have you seen

Because the character development and dialogue are usually up there when it comes to considering the greatest movie of all time. I love T2, it's probably in my top 15 or so. But it's absolutely not the greatest film of all time. I'd say the Matrix is a much better action movie itself.

Objectively and subjectively.