I like your car engine analogy; car's have the same level of widespread use as computers, yet I would wager a large percentage of people would struggle to perform much in term of car maintenance. Anecdotally, I know a multitude of people who have no idea how their car engine works, so much so they would not know how to check the oil level.

As a further point, drivers are (with edge case exceptions) not kept away or locked down from performing any work on their vehicle, yet in most cases they would still prefer to pass the responsibility on to a trusted professional.