alt Hacker NewsThere's a multitude of evidence that points to the success of the ACA from a cost perspective (among other things).
Cost of healthcare for individuals is not a good metric to judge by. The ecosystem of hospitals, patients, doctors, insurers, health systems, and the federal government is complex and you're not going to get a clear picture of the overall impact of the ACA by looking as something as simple as cost savings.
One example, hospitals are required to treat patients whether or not they hold insurance. The hospital foots the bill for that care and it's a major reason why hospitals shut down (especially in underserved communities). Getting more people on insurance plans was a direct factor is keeping many struggling hospitals and health systems afloat.
https://www.statnews.com/2019/03/22/affordable-care-act-cont...
https://www.networkforphl.org/news-insights/the-affordable-c...
https://www.cbpp.org/research/health/chart-book-accomplishme...
If the ACA was so successful at reducing coats we wouldn't still be having discussions like this about the excessive costs of both care and insurance in the US.
We will never know how costs would have changed if we didn't implement the ACA, and cost is not the only metric of success. But it clearly hasn't led us to a place where people feel okay with what the industry costs.