It mandated that Americans must purchase a product.  If they didn't conform, they would be subject to a fine, but that would put Mr. Roberts on the wrong side of history vis a vis Obama's legacy.  Not to worry:  We'll call it a tax, although, I've heard, 'tax' is nowhere in the language of the legislation. 

The main problems were high costs of previous medical plans and the high number of uninsured. 

The uninsured could have been addressed by legislation written just for them.  The high costs were not alleviated:  Today, a couple, purchasing medical insurance, on their own, is likely to pay $2,700 a month with a $12,000 deductible. (I heard two folks on a radio call-in say this, or claim numbers that come close). 

Are there 20-million uninsured, still?  That wasn't supposed to be the case.  It can't be because the fine was eliminated, because the fine was way, way lower than monthly insurance premiums; they eschewed purchasing insurance at the get-go.