Dialysis also requires expensive medicine, like e.g. EPO, which contributes to a non negligeable part of the cost. The 77000 $ / patient surprised me a little because the figures I have heard in France (family members involved in dialysis treatment)are actually higher, not lower.

Well, the heart, lungs and to some extent kidneys are pretty simple to emulate, but the full suite of chemical functions performed by, say, the liver are actually pretty tough. That said, the power concerns are indeed another serious obstacle.