Dialysis is a highly regulated activity; is not just having the machines. You need a water treatment plant and pay for 1 or 2 technicians to run it , you need to monitor for infectoins and security issues, you need a place to do it that meets all the technical requirements satisfactory to medicare. You need a dietician, SW , a bunch of nurses , NPs and PAs to staff the patients and administrative staff.
A lot of money goes to overhead expenses and the reimbursement has been shrinking over time.
I think you make more money buying and holding gold that getting into all this headache. If I was rich the last thing I would do with my money would be to open a dialysis unit !!!