Ph.D's get paid a pittance relative to what they do... and for like 3-5 years.

Apprenticeships for things like plumbers and electricians pay a decent wage interspersed with education.

On the long term a Ph.D may do better than a Master Electrician, but in the short term it's a way better deal. My friend out of HS who started working for Nissan and then Infinity was making 60k+ before he was 21. He's capped at around that much -- like 60-70k -- but most of our high-school friend circle wasn't making that kind of money until our late 20s (and at least one became a teacher, and still doesn't get that much in terms of pure cash comp).

I wouldn't know, I'm just a high school dropout, but if they barrier of entry to getting into a PhD "guild-system" is to also go through Associates, Bachelor, and Master degree, then I don't think its worthwhile for 90% of jobs that only require technical mastery.