I'm not sure about this. Space is big and these satellite constellations are getting very large, with lots of redundancy. I know I'm sort of arguing against my previous point, but bear with me for a sec. You'd need an anti-satellite system that either destroys them kinetically (accepting the cost of the debris field) or one that breaks them electronically (an EMP or another device that defeats them electronically). The United States' underlying philosophy on advanced weapons has, for a long time, been precision so I could see the emergence of in-orbit interception & defeat/disable platforms. But you'd need a lot of them for the doctrine to be effective, which means a lot of mass-to-orbit logistics. Adversaries do not have this, so I would expect e.g. PRC to have an alternate strategy of rendering entire orbits unusable or dangerous, which I think is easier.

Regarding your missile platform question, there are several companies that already manufacturing loitering munitions, and long-range loitering cruise missiles are on the roadmap, so to speak.

> I wonder why they aren't stsrting wth missle platforms instead

Price and ease of manufacture. Missiles are expensive and hard to build.