Sure, you can find some videos of people making a wooden clock online. It's much harder to find master craftsman making a watch. A few PHD students putting together an electric car vs. someone at GM actually designing a car. Home cook vs. Five Star Chef.
Granted, generally an amateur is fine. But, don't be surprised if there making several mistakes without noticing.
That applies to occupations, not to hobbies. I.e. those who can't find a proper job using their skill go on to teach that skill.
It does not however apply to the most valuable content - one made not for money, but out of love for the subject. A lot of masters in all occupations simply like to share. Our industry is probably the best example - it's almost entirely built upon masters who gave away their knowledge. But it happens in other industries too.
in sincerely doubt that...