That is just a despicable generalization. There are many, many dedicated, diligent and loyal teachers that do way more than their duty calls to teach their learners.
My loving wife. She's the polar opposite of the WAF cliché. She doesn't care what is making the music, as long as the music is good, and she has an excellent ear.
Top notch components and parts are as much available to the DIY enthusiast as is to the commercial guys, albeit at a higher price. Having said that, the DIY guy is more likely to use top notch parts due to his enthusiasm.