Not going to argue with you about this, just look at the current IPERS website, average employees cannot opt out. I know I was never given the chance to when I started in 1985, nor was my wife when she started. You can not opt out today, I am not saying there might have been a few years that people were allowed too, but that was not the case before and after when your wife started. The only people that can opt out are elected officials, certain city positions and a few select other jobs. Your wife as a teacher would not be in either of those groups.
As too how much I would have in if I had a 401K program, we will never know. I do know many included myself that lost over half their retirement in other accounts, during the last downturn in the economy under Bush Jr.
You do realize that pension funds often suffer similar losses. At least in this low interest rate environment