Because the implementation effectively just gave the insurers a locked market.
Want a real ACA do what most of the world did - take profit out of the healthcare business.
Put in a 5 year plan that insurers have to convert to non for profit orgs.
Single payer won't work in the US most of the world doesn't use it but has some sort of hybrid system.
The common ground is that private providers are often non for profit or have to invest a substnetial percentage of their profit back into health services they provide for free or at highly discounted rates.
And non for profit doesn't mean they can't make money it just means they don't pay dividends to shareholders and invest their profits back into healthcare.
