Investors don't care much for immediate annuities. They won't permit changes to Social Security and would happily swap their 401(k) plans for traditional pensions, but even though immediate annuities also offer guaranteed monthly income, their sales languish.
The name doesn't help. "Annuity" is soulless. It sounds like an actuarial calculation. (Which it is, but sometimes the truth need not be told.) Nor does the product's complexity. Would you like a fixed annuity or variable? Market-value-adjusted or book? Lifetime or fixed period? Single period or multiple period? For today or deferred? "Erm, I don't know, can't I just have an annuity?"