Because that's the only 'fair' way to do it.
One such case was Debbie Hirst’s. Her breast cancer had metastasized, and the health service would not provide her with Avastin, a drug that is widely used in the United States and Europe to keep such cancers at bay. So, with her oncologist’s support, she decided last year to try to pay the $120,000 cost herself, while continuing with the rest of her publicly financed treatment.
By December, she had raised $20,000 and was preparing to sell her house to raise more. But then the government, which had tacitly allowed such arrangements before, put its foot down. Mrs. Hirst heard the news from her doctor.
“He looked at me and said: ‘I’m so sorry, Debbie. I’ve had my wrists slapped from the people upstairs, and I can no longer offer you that service,’ ” Mrs. Hirst said in an interview.
“I said, ‘Where does that leave me?’ He said, ‘If you pay for Avastin, you’ll have to pay for everything’ ” — in other words, for all her cancer treatment, far more than she could afford.
Officials said that allowing Mrs. Hirst and others like her to pay for extra drugs to supplement government care would violate the philosophy of the health service by giving richer patients an unfair advantage over poorer ones.
Patients “cannot, in one episode of treatment, be treated on the N.H.S. and then allowed, as part of the same episode and the same treatment, to pay money for more drugs,” the health secretary, Alan Johnson, told Parliament.
“That way lies the end of the founding principles of the N.H.S.,” Mr. Johnson said.
You better believe I'm setting myself up to be able to pay for it on my own.
Via Hit and Run