If everyone was forced to use healthcare.gov to purchase health insurance, then we could have a viable market similar to auto or home insurance, where consumers reward the insurance companies that negotiate lower healthcare costs by signing up for their lower premiums.
It is the obfuscation of costs by way of the tax advantage given to employers subsidizing healthcare that greatly reduces the insurability of the people on healthcare.gov since many healthy people are silo’d out into lower risk employer pools, and therefore reduces the amount of insurers that can exist and compete for business.