Looking at "Table 1", the 2022 value for the US is 12,555 in PPP international dollars. 1/4 of that would be 3139. The only countries below 3200 are countries with a significantly lower development level than the US: Mexico, Colombia, Costa Rica, Turkey, Slovakia, Chile, Hungary, Poland, Greece and so on.

US peer countries in terms of development would be countries like Germany, France, Canada, Belgium, Australia, Denmark, UK, Japan, etc. Of those, only Japan and the UK are below 6278, which would be half the cost of the US system. Canada is close though at 6319. And some, like Germany and Switzerland are closer to 3/4 of the US costs.

I think it's more fair to say that the US could have a much better healthcare system that also covered everybody in the country for half the cost if it switched to a Universal system. To be able to do it for 1/4 the cost, the US would have to have an economy like Poland, Lithuania, Latvia, Estonia, etc. Wages and costs would have to be significantly lower. To put it in perspective, as a Canadian if they think they'd have a functional healthcare system if the funding was cut in half. I can pretty much guarantee you they'd say no.