For those who don't understand conceptual math, here is an example:
Jim Workman is an engineer, and gets a no-cost (to him) high-end family insurance plan from his employer costing his employer $20,000. Let's say average family plans cost $12,000.
That $20,000 is counted in the amount folks pay every year for health costs. All the estimates of how to pay for M4A start with assuming all the money paid by all the employers ends up in a communal pot. All estimates also admit MORE taxes will also be needed, on top of all the money currently paid for employer plans.
If we get M4A, it won't be as good as the high-end plan, since higher-end plans cost MORE, and all the estimates have been for a Medicare-level plan, which is LESS.
If Jim's boss has to pay $20K for a $12K-value plan, he might feel cheated, and rightly so. If Jim has to pay MORE taxes to boot, he'll definitely feel cheated.
If, however, Jim's boss only has to pay $12K, the money SUBTRACTED from the $20K will have to be ADDED somewhere else in the equation for it to balance, in the "MORE taxes" column.
If Jim's boss raises his wages $8K, that's taxable money, so Jim pays ~$2K MORE in taxes, in addition to the MORE taxes needed to implement M4A.
If you can convince Jim and his deep-pocket friends to pay thousands more in order to get a plan worth thousands less, you'll win.