Here are the facts:
1) The US had increased life expectancy >1 year every decade from 1900-1910
2) Global indices of first-world countries indicate that the rest of the world is continuing to experience the same slow but steady increase in survival we've seen since the '70s (see, for example,
this). And the US lags behind most other developed nations. So you can't argue we're bumping into some natural limit.
What changed in this country in this decade?
We managed to increase life expectancy in the 30s. This decade has seen solid overall economic growth, coupled to a decline in survival for the first time in the CDC dataset. It is very clear - if the objective of healthcare is fundamentally to keep people alive, the ACA is an abject failure.