Seems to me that governments, including American Federal and State governments, do it all the time. In fact, it's so common, that I wonder if that's the main function of government.
Excluding ethics / philosophy of that kind of seizure, it's just a hard computational problem to orchestrate a centralized reform of something so complex. It becomes impossible when the system being reformed gets involved, buying politicians on both sides to impact the future and influencing public perception. And how could they not? It's hard to even fathom the stakes: a highly centralized industry capturing 10% of US GDP.
That's why, at the risk of being a tech culture charicature, I think business innovation from outside the industry is more likely to make a dent than politics.
As an outsider getting occasional (and highly combative) tidbits of the last american health system debate... It seems like a tall order. Doesn't seem possible to make a reform that (a) half the people don't think is the devil's work and (b) works in theory, which is important to Americans and (c) works in practice.