> Why can you not just give them their pills and charge them the real amount.

You can, you would just end up without income at best, or charged with a crime and imprisoned at worst.

Also, all these complexities in healthcare exist due to 90% not being able to afford it, so the complexities are to paper over politically unpopular subsidies from various groups of people to other groups of people, in varying amounts. The other part of it is the nebulous costs of liability, that potentially reach into the millions for each interaction.