We honestly need to expect a certain level of competency from people.
No. We honestly need to expect a certain level of competency from ENGINEERS. People are allowed to be stupid. Way back in the days of the first air-brakes, they used air pressure to apply the brakes. What happened when the system failed and air pressure was lost? The brakes failed. Nowadays you design a system where you need air pressure to REMOVE the brake. Now if your system fails, the brakes are applied - orders of magnitude safer than no brakes. Electrical devices are grounded. Commercial jets can fly with only a single engine. Etc.
Fail safes are necessary because the universe and people don't always co-operate. So when the shit hits the fan, you try to kill as few people as possible. Just hacking something together and throwing it out to the public isn't good enough - that's irresponsible design. If a guy kills himself with your product you need to be able to show that he went to extreme lengths to do so.