First, while most people who have insurance assume they always will, this is not true. If you work for a small company, that company may find it too expensive to maintain access -- poof, your insurance is gone. An accident or illness can either take you out of the workforce unexpectedly, or can be reason for an insurer to discontinue services -- poof. You can lose your job (yes, even you), and -- poof. You can find yourself under-employed -- poof. You could easily find ourself among the uninsured. Many Americans spend some portion of their adult wage-earning years uninsured. If they are lucky, they won't need health care during that time. However, luck is not dependable.
Second, people who do not have health insurance are part of our community and still need health care. When people do not have a regular provider, someone to call when a health problem first arrises, they frequently go without care. After time, the problem usually gets worse for neglect, and eventually, the problem becomes an emergency. Emergency room care is more expensive, for both the individual and the community, financially and physically. Frequently problems that were easily treatable earlier become expensive, painful, traumatic experiences by the time they are seen in the ER. Other times they are fatal. Privacy is limited; continuity of care is even more limited; other infections are usually available to pick up while you visit. And all at an astronomical cost.
The one advantage in an emergency room is that you can't be turned away. Whether you can pay or not, whether you have coverage or not, you will get the care you need.
As a community, we all pay for this higher-cost care. We also all pay for the disability and decreased productivity that happens when diseases and injuries are allowed to get worse (for lack of other options). Preventative care, early detection, regular check-ups, all cost far less than emergency care for late-stage diagnosis and treatment. If we vote only from self-interest, it is in our interest to make sure that everyone in our community (which is the nation if we are honest with ourselves) has access to health care.
Let's pay less by taking better care of each other from the start.