Even with the individual mandate, it seems self evident that incentives are for private insurance companies to happily take in the extra premiums from healthy p

Even with the individual mandate, it seems self evident that incentives are for private insurance companies to happily take in the extra premiums from healthy people, and then drop or have prohibitively high premiums after people get sick. The medical loss ratio tries to mitigate this, but just kicks the can down the road where the incentive becomes to dump the money into administrative overhead and self-dealing with providers/pharmacies run by affiliated companies.