That's just not the thought process. A vacuum with a cheap motor isn't going to have trouble hurting your fingers if you stick them in the brush at the right an

That's just not the thought process. A vacuum with a cheap motor isn't going to have trouble hurting your fingers if you stick them in the brush at the right angle. But the bearings will wear out in 5 years. Another is drills with cheap housings or gears. The drill will happily rip a glove off and de-skin you. But it'll still wear out faster than if it had metal gears or a tougher housing. Usually safety is an expense. Extra sensors, very carefully engineered weak links that suddenly break under load. Another counter example to your point is my automated litter box. It has a pinch sensor for safety reasons, which is made of two metal contacts. This sensor is directly above the pee/poop so it corrodes and I have to take out like 20 screws in a machine filled with poop to fix it, like every year. They could just have added a plastic cover and one screw to protect the contacts, but no. Probably the only thing I can think of to support your argument is cars. The front end of a car is plastic and metal designed to absorb energy in an impact. But household stuff...