icbms and hypersonics exist, theres no defense against the top end anywhere atm.
if you're in a war where people are shooting your satellites out of the sky you're past the point where defenses matter. theres no grey war in space like russia hiring people to blow up stuff in europe and very few states could take out multiple satellites in space.
beyond that if we ever did get to that point, you could develop anti missile tech in space, you effectively have the high ground sitting at the top of the gravity well.
if you're in a war where people are shooting your satellites out of the sky you're past the point where defenses matter. theres no grey war in space like russia hiring people to blow up stuff in europe and very few states could take out multiple satellites in space.
beyond that if we ever did get to that point, you could develop anti missile tech in space, you effectively have the high ground sitting at the top of the gravity well.