"The main difference between Social Security Disability (SSDI) and Supplemental Security Income (SSI) is the fact that SSDI is available to workers who have accumulated a sufficient number of work credits, while SSI disability benefits are available to low-income individuals who have either never worked or who haven't..."

So technically it IS disability.

They usually switch people to medicare after the 2 year waiting period. If you cant afford it, thats why they have the extra help and other programs.