You say it won't come down, but that's because the US is in it's own ballgame. In most other advanced western country healthcare "only" accounts for 7~11% of GDP.
The chart on [0] is incredible. I also shows how much that percentage has grown over the last 45 years.
[0] https://en.wikipedia.org/wiki/List_of_countries_by_total_hea... [1] Source data OECD: https://stats.oecd.org/Index.aspx?DataSetCode=SHA
I agree it's higher, and while some of this is waste, some of the higher proportion is explained by the US being richer.
Whether it will come down, I guess that's partly a forecasting guess. Will the healthcare sector be a smaller part of the economy in 10, 20 years? Employ fewer people? I would be extremely surprised if this happened in any advanced country.
Pensions are in a way similar. When steelworkers retiring at 65 could expect on average a few golden years, then deciding how to pay for that wasn't such a huge deal. When they can expect a third of their lifetime to be in retirement, then it's very different.