I think instead of being coached, barbell lifts require learning them, as opposed to just doing the movements described on the machines' pictures. The difference means that anyone right now can go to YouTube and look up the proper form for back squatting or overhead pressing, as long as they want to invest a bit of time researching and then practicing (that is, you don't absolutely need to pay someone to teach you).

Agree otherwise, though. I think our culture needs to emphasize the importance of strength training for health (over casual gym attendance for hypertrophy and self-esteem).