So, it's not particularly a Republican (or Democratic) problem (regarding the OP). It's a problem of short sightedness and greed?
I believe it's a multifaceted issue with many factors. There's no one thing.
Heathcare is expensive by it's very nature. There's a Caste of health professionals; doctors, nurses, technicians, therapists and support staff (salary, benefits, retirement). There's the physical plant - buildings, equipment, instruments and vehicles. Instruments are particularly and absurdly expensive. $250.00 for a stainless steel screw or plate - you'll need a dozen to fix your broken leg. $6000.00 for s Stryker drill you wouldn't pay $25.00 for in a Builder's Square. A set of stainless steel instruments is $10,000 - $25,000. An Olympus flexible scope is on the order of $15,000.00 to $50,000.00. CAT Scan, MRI, Rad/Onc machines - all in the millions of dollars. All overpriced because of locked-in contracts and surgeon's demands.
Our surgeons were convinced by sales reps that they needed DaVinci robots ($2,000,000.00 each) with a complete system of robotic arms, scopes and accessories. Before long, a second gen system was purchased, and then a third. The surgeons now use just the third gen system but all three were purchased at great expense - payed for by patients. I could go on, and probably will in further posts.
The American medical insurance industry also have their costs; half a million employees across the country - their salaries, benefits and retirement plans - buildings, computer systems, overhead, overpaid CEO's. In Canada all this is handled cheaply by a few government bureaucrats.
Furthermore, numerous agencies; Joint Commision, the CDC, the AMA, AORN, AAMI (literally dozens) are collectively a driving force for improvement in healthcare without regard to rising prices.
Clearly everyone has their pet theories, but I've been working in hospitals for nearly twenty years and medicine is inherently expensive and will become more so in the future. As healthcare improves, health costs will rise.
Clearly also, the American private insurance system is no longer viable, It is too cumbersome, it does not serve the poor, and corporations are gradually divesting themselves of employee benefits in the Gig economy.
America really has little choice. Only the Federal Government has the resources to provide health coverage for 300 million people.