You may not. But the politics of the situation--and indeed even the rhetoric of many single-payer supporters--suggest that in practice the promised cost-cutting won't materialize. The problem is in denying the existence of any trade-offs at all and assuming, or promising, that single-payer will be everything to everyone.
Let me give you two examples.
First, the post below yours:
Variants of this argument have been by lots of single-payer supporters. Even Bernie Sanders makes it. And it may be more or less true! But if we just end up shuffling people around, whatever the merits of that, we aren't going to achieve cost savings. We'll still spend what we do, just a little differently. Which is probably the most realistic scenario for how single-payer would play out.
Second, another ongoing thread:
Hospital Closings.
The example is a rural hospital in Tennessee that is closing its doors. That hospital is a cost in the health care system. It could be a good cost or a bad cost, justifiable or not, necessary or unnecessary. But in order for that hospital to keep its doors open, someone has to cover that cost. That isn't currently happening so it's closing up.
There are multiple folks in that thread who argue that single-payer would save that hospital and others in that situation. It might! The single-payer might direct cash into those kinds of struggling facilities to cover their costs and keep them afloat. But that's an added expense to the system. Again, it might be a good one, that's open to debate. But arguing that single-payer will pump new money into health care infrastructure that isn't economically viable runs entirely counter to the argument that it's going to lower spending and save money. And yet I would wager that every person in that thread who argued single-payer can save such hospitals would also argue that it's going to save money.
This is the denial of tradeoffs and the compartmentalization of "costs" that I've been critical of. It cheapens the discussion of single-payer because it obscures what we're actually talking about when it comes to health care and what single-payer does and does not offer.