I'd like to think a single payer would work, but the U.S. government has proven it cannot run an integrated health system.  One such example is the VA.  Medicaid is consuming more of the budget quite simply because there are more people consuming healthcare.  When something is free, you use more of it - it is really that simple.  If you read some of the hospital rating reports, the idea that increasing the Medicaid eligibility has backfired as the increased volume (e.g. new patients who've never accessed the health system before) and transfer of patients to Medicaid from commercial insurance (due to the ACA regulations around minimum coverage causing small biz to drop plans) has outweighed the reductions in charity care write-offs.  

I wish it were otherwise, but Americans  want to be lazy, eat like crap, consume drugs legal or illegal, and at the same time demand their right to free healthcare.  Unlike countries were single payer works, there is no social contract to be responsible.