Thanks for the detailed response.
What in your estimation was the average percentage return for the 401(k)’s that didn’t have the funds invested in —any— stocks?
Hard to say without knowing what the funds were invested in, but as a guess, over the past decade, 1 or 2%. Probably didn't even keep up with inflation. If you have a 401(k) with that kind of asset allocation, and have records, the XIRR function in EXCEL will tell you exactly what your return was. It might take a few hours to understand the directions and input everything.
Of course inflation is another ball of worms. There are a lot of measures of inflation. I can tell you with great confidence that my personal inflation, and probably yours also, has been a lot higher than any of the government estimates.
But, coming back to returns, not having any 401(k) money in stocks wold be extreme financial malfeasance. Probably worthy of a lawsuit, except that the only winners would be lawyers.
From your screen name, I will guess that you were born in 1957. If you do not have a company pension and SS plus a very small 401(k) is going to be your only retirement income, you are not in good shape.
If I were in that predicament, I would start seriously looking into retirement in some of the expat communities in very low cost of living areas. You can find communities of US citizens retired in small areas in Costa Rico, Mexico, some places in Asia, etc. A dollar goes a lot further there than it does in the US.
There is just no way to sugar coat the fact that minimal savings at 61 isn't going to translate into desirable living in the US, unless you have relatives or children who can help.
OTOH, I will make the prediction that some way will be found to "fix" SS, probably in such a way as to maintain benefits for lower income people while introducing a means test of some sort for people who have saved on their own. I fully expect to be totally screwed by whatever is done.
Now some people will look at that and think that since I don't really "need" the money, it is a good solution. My only response will be that I was taxed for 40 years with the promise that I would be paid a SS benefit when I was old. Now that I am too old to do anything about it, there is a certain moral issue associated with snatching the promised benefit away from me.
Of course, since I saw this coming, I started SS benefits at the earliest possible opportunity, and I don't think they will want what has already been paid back. I won't be hurt badly enough to ferment revolution. OTOH I will vote my interests.