That's the important point. The costs and risks are on the org. They can guarantee the pension with low risk investments or dollar equivalents and have effectively no risk or they can try higher risk investments in an effort to save money but at the end of the day the employee/pensioner gets the amounts promised from the beginning.
1. They can allocate measurably portions of it to low risk investments, bonds, etc.
2. A qualified direct benefit plan (which is referred to as a pension) has guarantees attached to it. Even if the company goes completely under and all that money bursts into flames, the PBGC (https://www.pbgc.gov/) will guarantee the payout of the pension to the pensioner and foot the bill.
I'm not trying to suggest that there aren't costs that need to be borne by someone but forcing the worker to bear those costs seems like it's quite obviously the wrong choice (they should be allowed to bear it if they want to though).