Speaking of Florida sinkholes: http://www.newser.com/story/243143/sinkhole-opens-up-in-front-of-trumps-mar-a-lago.html
Here's a good review of a comprehensive Cali dive into Single Payer costs, benefits and challenges. http://mattbruenig.com/2017/05/22/californias-surprisingly-cheap-single-payer-plan/
What is worth noting on that is that this is just the claims of the bill's sponsor as the bill itself has not been made available for independent scoring. Also unclear is if the state would have to bare the full cost or if Federal programs (Medicare, Medicaid, S-Chip, VA, etc...) could be tapped to pass on some of these expenses to the Federal level. Yes, $400 billion is a lot even by California standards and single payer is a better, cheaper system but without the feds picking up at least half the cost it is simply a budget buster. The biggest advantage with single payer is it has economies of scale as it has the wildest possible insurance pool thus giving you the lowest possible per unit price. That is why a state by state approach is less efficient than a whole nation approach.