Sure they are - the s300 system for example can be redployed quite rapidly & some like Buk have the radar even integrated with the launcher.

Also only the radar really transmits, so even if you hit it the, separate launchers might still be intact & guided by another radar if you don't destroy them.

This is why modern remotely guided middle strike drones are so dangerous for SAMs - they can basically search an area for all the SAM system components and destroy them all or most of them. Potentially much more effective than a homing missile hitting just the radar at maximum.