If your 401(k) was like the state lottery, it would be worth zero right now. Does your 401(k) statement read zero?
I have given at least 10% of my salary to my 401(k) since 1985. Even though it took a beating the last three years, I can still buy several houses with it. That's a much wiser choice than if I used that money for lottery tickets.
To me, it's a matter of trust. I haven't seen any evidence of states rigging their lotteries. Can't say the same for Wall Street.