The long awaited alternative to Obamacare is now out in the open. It gets rid of the requirement to purchase health insurance (the mandate),. Vox offers s simple way to understand why this will not work. Here it is in a nutshell
Since healthy people are punished for restarting coverage, they might decide to hold out until they get sick.
Meanwhile, sicker people might be more willing to pay the penalty since they need care.
That leads to a sicker insurance pool, higher costs for everyone who has coverage, and even less incentive for healthier people to join the pool.
The bottom line here — if you do not have a single payer system (national health care), and want universal coverage, you have no policy choice but to impose the mandate. If you do not, healthy people will not buy coverage and the system will not work.