> you can fire a THAAD at a Starlink satellite as well.

You can fire a THAAD at one Starlink satellite, but probably not at 8000 of them.

For comparison we’re currently producing THAAD interceptors at a rate of 96 a year (though Lockheed is aiming to increase it to 400).

Exactly; it's a limited and very expensive capability. Nobody would want to spend it on a $100k stratospheric flying vehicle, if the latter existed. It does not exist though, if you do not count weather balloons.