Cutting Medicare to give people BI would leave the people who need Medicare in the lurch, because there's no way in hell that you're going to get the medical treatment you need on that $12k.
Medicare provides for the sick by levying a disproportionate cost:benefit on the healthy. Distributing BI to the healthy and sick alike in lieu of Medicare eliminates that.
You might also notice the "Total Federal Spending" line in that chart you linked is $3.6 trillion...a full $200 billion short of the $3.8b mark.
The article proposes that everyone (healthy or sick, young and old) pay $350/month out of their BI for health insurance. Would that be enough to replace Medicare?
Sure, but all you've done is keep medicare in place and reduce BI to $7800/year. Note that medicare is only available to people over 65 in most cases - it isn't generalized health insurance, so now anyone under 65 needs to pay for health insurance on top of the Medicare tax. Which is exactly how it is now anyway.
Medicare provides for the sick by levying a disproportionate cost:benefit on the healthy. Distributing BI to the healthy and sick alike in lieu of Medicare eliminates that.
You might also notice the "Total Federal Spending" line in that chart you linked is $3.6 trillion...a full $200 billion short of the $3.8b mark.