Wanna see how much force it takes? Place the pressure plate, face down, with a clutch plate installed, bolted to a flywheel. Now place that flywheel in a shop hydraulic press on top of a heavy duty postage or shipping scale. Then engage the press and see what it takes in pounds just to deflect those fingers inward about 3/8ths of an inch, which is what it takes to release the disc. You will be STAGGERED, I promise.
Remember, the entire inertial weight of the vehicle depends on that pressure to propel the vehicle, uphill in fourth gear, even! Imagine what that needs. The actual figure varies greatly with the weight of the machine and the power of the engine, but it's huge...
Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon