I'm not arguing that having more things regulated federally or having a completely federally regulated America is going to be better. It seems like you think of lawmakers and lobbyists as adversarial, not necesarily untrue, but it it is hard to argue in any direction since they will always be working against you to their benefit.
I was pointing out that this is what makes America "varied" compared to other countries and it will introduce complications and variations in how a healthcare system is going to work for it's citizens if they do try to mimick Canada, UK, etc.
I would also hope that the hospitals have a bit more autonomy and they aren't hamstrung by congress deciding they aren't allowed to spend more than 5mn on sedatives or some other really narrow and specific budget.
And having one federal system creates corruption - a one-stop shop for lobbyists.
Do you really want congress and the president deciding on budgets for various illness, prescription costs, what is covered, etc?