ACA is NOT insurance. ACA is more like a co-op, a communist-like shared cost pool. All people (all risks) are “forced” to jump in the pool evenn if they can’t swim and pay what they can and take out what they need.
Constant tweaking and extreme command and control must be applied for the plan to break even financially.
Since some issues cannot be controlled, an aging demographic for example, increasingly expensive R&D, rationing and behavioral controls (wear your seatbelts) MUST be applied from time-to-time.