Re: Cost is the smaller concern
"2) What about the interaction between life support machinery and desktop computers? Has anyone actually considered that this is perhaps the main reason why the NHS is still on older versions of Windows? Is someone going to make every ECG or Kidney Dialysis machine Windows 10-compliant?"
This is precisely why those interfaces should be documented. In reality they are going to be pretty basic but would require some dedicated tinkering to determine the protocol and write some new drivers. The NHS really has been in the hands of some unscrupulous computer companies.
In manufacturing all those protocols are well documents with hundreds of companies able to support them. Even 40 year old CNC gear is supported.