I agree that it makes no sense as an investment. However, I'm left helping pick up the pieces
If the plan could change the annuitant to the individual, my thinking is that the distribution of the annuity would not be a taxable event.
"If a trust described in section 401(a) and exempt under section 501(a) purchases an annuity contract for an employee and distributes it to the employee in a year in which the trust is exempt, and the contract contains a cash surrender value which may be available to an employee by surrendering the contract, such cash surrender value will not be considered income to the employee unless and until the contract is surrendered." Reg. 1.402(a)-1(a)(2).
I know that typically a plan transfers the annuity prior to payments beginning, but I don't see anything that changes the outcome merely because payments have been made for 20 years already. Of course, all subsequent payments to whom would be taxable and a 1099-R issued by the insurance company.