Just because you regret a decision doesn't mean that at the time it wasn't voluntary. Lock in is not force. If you buy something that requires a certain expendable item to function you know you are dependent on it being available. I'd like to be able to buy parts for my 20 year old lawn mower but the manufacturer refuses to support it anymore.
Food, lodging, and medicine are certainly voluntary. You can. Jose to be homeless or live in the wilderness and live off the land. It just so happens that voluntary exchange has made us so wealthy nobody even thinks it's an option.