A jam-resistant device interfaced to a computer-controlled actuation system that has to respond fast enough to hit 9g targets. I don't know why we're discussing Pantsir-S1 anyway, there's no evidence it's hit a ballistic missile or rocket, and I question the ability of a radio command missile to do so. So far you have provided to evidence of cost or ability.
Since forever when it's part of a control system and has to respond very fast. High demand control systems are expensive. Even far less complex low-end ABS or TCS control modules for cars, minus actuation system, radio link, proximity fuse, warhead, rocket motors, fuel and missile costs £1,000, the switch is another £100. You're dreaming if you think SAMs cost <$100k.
Like I said, find me actual hard proof from defence budget reports (not unofficial web gossip), that any non-MANPADS SAM costs <$100k in 2022. It would be a start if you could even prove there's a MANPADS that does though. Even a Stinger is $120k and you ain't shoot down rockets with that.