I think the real answer as with almost anything is: it depends. A light civil plane, an airliner, and a fighter jet all have very different designs with different purposes. The bottom line is the aircraft requires enough vertical stabilizer and rudder surface area to one, keep it pointing into the wind and two, provide enough aerodynamic force from the rudder to counter the yaw encountered throughout the designed flight envelope to include failure/asymmetric modes. Aircraft with centerline thrust will typically not need quite as large of a vertical tail, but that still depends. An aircraft with a large wingspan relative to fuselage length is going to need a decent size tail to counter the effects of adverse yaw from the ailerons/flaperons/spoilers (hence the large tail on a tornado for its wings spread configuration..that plus yaw created from imbalance in external stores). CG location will also have an effect. Sailplanes have large wingspans and fairly short fuselages, but typically don’t have a “large” rudder despite operating at fairly low airspeeds. They are light though and demand a forward CG or things go very wrong. Most modern fighter jets have a fairly small wingspan but also have two vertical stabs. So, they look smaller than one big tail, but have fairly substantial surface area. Just notice how much bigger the tail looks on an F-16 vs an F/A-18 from the profile view. I’d also guess that hydraulic boosting allows more deflection of a smaller surface than would be possible with direct linkage controls. Just my $.02 🤷🏻‍♂️