The argument is that in the event of an industry wide systemic failure the state's insurance guarantee fund may become tapped. The irony is that market crash (which could lead to systemic failure) is the exact thing that lures investors to annuities in the first place. So are you really protected by an annuity?
But you must compare the annuity with normal investments. You want the most bang for the bucks that you have saved up. They have to ask, given the amount of risk that they want to take, which is likely to give them the highest return?
But how likely is that over a long time period of 10, 15 or 20 years? After the insurance industry stacks the deck in their favor (through caps and participation, and doing so after they pay Mr. Annuity salesman his big commission, pay for all of their overhead, and STILL make a profit! They know it's a safe bet.
That's not what deep discount brokerage firms like E Trade, AmeriTrade, Regal Securities, and ScottTrade are all about. No comparison. I can buy 100K of BND and 100K of VOO for less than $20! An annuity usually turns out to be the most expensive "free dinner" you will ever eat at some "free retirement seminar".