So I'll take this response as you have no actual solution or suggested plan to improve the situation, and only desire to complain about it? Understood. Moving on.
I would say do I think a teacher (your own original mention) should make more money and not have to work two jobs or buy their own school supplies or etc? Absolutely. Do I think John Doe at the car wash or Jimmy Jim in aisle 7 should make as much as people significantly more qualified at higher level jobs? Absolutely not.
No one is forced to do anything correct? This we can agree on. So as a responsible adult, you make a decision to work a job. You go to an interview, the employer offers you a schedule and a salary correct? You have the option to accept this salary, or decline this salary correct? If you feel the pay is too low for what you are seeking, you should decline and accept a job with pay relative to your desires correct? If you are unqualified for a higher paying job you should obtain the qualifications to receive the higher paying job you desire correct? Where do you disagree with me in this paragraph.
My stance holds that mediocre jobs should not be considered career jobs, and in turn will not reward you with career level pay. Everyone in America knows that the cashier at Walmart makes crap pay. This is no surprise. This should be a job that you do as a stepping stone, extra cash while in college, first job at 17 years old, grind it out until you're promoted to manager, etc. The job before you eventually transition into a better career path as you develop as a person. Why do you feel someone should be able to work crap jobs for decades and make as much money as people who put in significantly more time, effort, and sacrifice into their career paths? If this isn't your stance then feel free to correct me, it just reads that this is what you are implying.
A job that doesn't exist? I am using the car wash example for the actual fact that my first job after high school was 35 hours a week at a car wash. My second job was as a security guard while in college making $8.50 an hour. Did it for a year. Then I did office assistance work for $10.50 an hour. These were my jobs in college while I focused on my future career development. Difference is I knew exactly what those jobs were, short term stops for some on-hand cash. Not career life fulfilling jobs.