Where are your facts health care costs plummeted?
For whom did they lower, because here is a FACT:
As Table 1 shows, the national average monthly premium paid in the individual market in 2013 was $244,
while by 2019 it was $558—more than doubling (a 129 percent increase) from 2013 to 2019.
Health care cost growth plummeted, it was near all-time lows in the years after the ACA passed. That's the total amount of spending on health care by Americans, not any cherry-picked market segment. The individual market is 5-6% of the American population, so trying to figure out what's happening to health care costs by looking at only that market segment makes little sense.
Anyway, per Trump's HHS, the average premium actually paid by families in the (individual) ACA marketplace in 2019 was $143 (HEALTH INSURANCE EXCHANGES 2019 OPEN ENROLLMENT REPORT | CMS). So hard to argue that the average family buying insurance on its own didn't come out ahead, anyway, even using your numbers.