This is too out there to predict with any hope of accuracy, but I suspect/hope planets will have a sort of anti-MAD, mutual perfect defensibility.

Orbit is a very offense-biased environment. It's much easier to hit a ship / missile with some high velocity pebbles and ruin its day than it is to survive those pebbles. New tech could radically shift that balance, but I don't think it will.

As long as war in orbit works like that, what you get is WW1-esque. An enormous no mans land with no cover and ample weaponry pointed at it. Now, if people are really insistent on fighting an offensive war that'll be WW1 style terrible. But I'm hopeful the only wars we'll see will be for independence, and that dynamic will just destroy the will to enforce control over distant bodies.