Your question indicates that you are not an investor, so I will give you a serious answer.
A 401(k) plan usually give participants a choice of how to allocate their investments. Typically there will be stock mutual funds, bond mutual funds, possibly target date retirement funds, etc. The particular investments will vary from plan to plan.
In general, most plans will allow a participant to allocate any percentage of their investments to any of the funds in the plan. Depending on the time period one looks at, bond funds have either done about as well as stocks, or miserably. Bond performance during the Obama years was miserable. Many people mistakenly believe that bond funds, or "stable value" funds are somehow more safe than stock investments. The reality is that they are guaranteed to lose out to inflation.
BUT this is not excuse for personal poor performance. Every single one of us should take personal responsibility for our own retirement. Do you think the government will take care of you in your old age? Maybe Santa will bring income -- just as probable.
It is highly likely that the final 1/4 to 1/3 of your life will be spent in retirement. It is our responsibility to educate ourselves about this time of our lives and prepare for it while we are in our earning years.
Some of us have. I had no secret training, I read commonly available magazines 30 years ago and switched to the internet when it became widespread. I once spent $300 on an investing course, but only after I had been a 401(k) participant for over a decade. It was money well spent. Other than that my investing education has been free.
Specific answer to you question is: "It depends on the particular non-stock 401(k), but probably performance was very poor." OTOH, every single 401(k) plan I have ever seen includes an option to invest in something like the S&P 500, or maybe the total stock market (the difference is very small).
If you have not chosen that in the past, the fault does not like with the government. But, it is a correctable problem. Change your 401(k) election to at least 80% stocks, and maximize your contribution. Even if you have to give up a little lifestyle now. You want retirement to be the golden years, not the Alpo years.
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?