THere are other middle men also, there is an industry of insurance brokers that take a cut to help companies wade through the plethora of bs associated with getting quotes and choosing an insurance company. There are also insurance company reps at every stage of the healthcare process, they review prescriptions, visit your hospital room to try and get you discharged sooner, they maintain call centers and data centers. The middle man aspect of marking up the services is just one layer of the insurance industrial complex. Also many Americans can't afford a checkup because they spend the money they do have on bullshit, it's not that we wake up one day and realize we don't have Medicare for all, we know we WILL have to pay for some healthcare (preventative or emergency) and still elect to eat out and spend beyond our means.