To understand how the individual market could destabilize in 2019, you have to take into account possible repeal of the individual mandate AND the executive order expanding loosely-regulated short-term insurance plans.
Short-term insurance plans are currently limited to three months and buying one of these plans does not satisfy the individual mandate.
With no individual mandate penalty and and an expansion of short-term plans that don't cover pre-existing conditions, healthy people would have an opportunity to get very cheap coverage outside of the ACA's regulated market.
With no individual mandate and short-term plans siphoning off healthy people, premiums in the ACA marketplace would rise a lot. Or, insurers would just throw up their hands and exit.
Insurers can likely manage any one change in isolation -- reductions in outreach, termination of CSR payments, individual mandate repeal, expansion of short-term plans, etc. But, could all those changes together be managed?
