Control won through fear requires constant maintenance.

Fear is expensive to run. It has to be topped up, it degrades everything else you might want, and it produces exactly the minimum behaviour required and nothing more. The moment the pressure lifts, so does the compliance, which means the arrangement can never be relaxed and never becomes self-sustaining.

If you are holding something together this way, look for one place to swap fear for a reason. It is slower and it stops requiring your constant presence.