The reason is no one has come up with a simple plan. Something like "every citizen is covered for anything. X number of dollars per month". But no we get offered a plan that's over one thousand pages long and you need to be a tax attorney to understand it.

That and probably an awful lot of people don't want to get another expensive entitlement started that not only will be in danger of going bankrupt at some point in the future but next to impossible to eliminate or reduce. (See Medicare/Medicaid and Social Security).