There's still a lot of crap cheap guitars out there, and some truly dreadful cheap amps
Not so lucky if you want e.g. a sax bigger than an alto, a bassoon, oboe, french horn... Some instruments just don't seem to have dirt cheap versions.
(No, I don't have a problem. I can stop any time!)
Running a music store means you'll want to sell the most expensive stuff with the higher margins so you have every incentive to convince people cheap stuff is crap. Why should I trust you?