Here's the Koch study btw: https://www.mercatus.org/system/files/blahous-costs-medicare... and if you read anything past the first page the study is a fairly scathing indictment of the current system, indicating not only would everyone be covered but it would actually likely lead to a net decrease in spending.

Here's the study that showed Medicare and Medicaid control costs better than private insurers: https://www.modernhealthcare.com/article/20190211/NEWS/19021...