Why are CVTs so prone to failure and so expensive to fix?

My go kart has a CVT. Because it has "infinite" gear ratios, there is no solid, locked in state of being "in gear". Like it would be if it has a simple chain drive. A direct chain drive could handle a ton of force. But like a mountain bike, even if you can change your gears, you have a limited number of discrete gears you can be in. But once you're in each one, you're IN THERE. But my CVT is just a rubber belt thats getting squeezed between two disks. It can never be strong. It can never be solidly in gear. Because it's infinitely adjustable, it always has to be just barely "in gear". If CVTs were solid and reliable somehow, they would be much more popular. Mine shifts automatically via it's integrated centrifugal clutch. But in trucks, you could use an actuator to control the gearing and have that be computer controlled, and you could accelerate something heavy like a tractor trailer by revving it up to its peak torque RPM and keeping it there all the way up to cruising speed. If the total "gear range" wasn't enough for a heavy load, you could put two or even three in line, all computer controlled, to keep the vehicle at the perfect gear ratio at all times. But of course you would destroy all the CVTs on the first acceleration because they all function by forcing all of your torque through some very tiny friction contact points. As as for my go kart, I don't want a computer controlled CVT but a manual shifter similar to how a snow blower lets you shift gears, but controlling the CVT state would actually be pretty neat and could work well. But all that said, unless there is some amazing breakthrough in ways to manufacture CVTs, I would never buy any vehicle with one that had more than 2 engine cylinders.