Only plumbers need to know how to fix a boiler and roofers/builders need to know how to fix a roof as these are skilled trades. If you want to learn how to do these things for yourself then great.
I agree that Accountants and financial advisors are good for that kind of thing but surely teaching children the basics in school would benefit them? By basics I even mean just the concepts. i.e paying your NI means you are eligible for certain benefits from the state.