Not all the mutuals were destroyed by carpetbaggers. There are dozens (though smaller than the big famous ones from the 1980s) today. Some instituted "anti-carpetbagger" rules to make themselves unappetising.

For example if the Society decides anybody who became a member fewer than ten years before the vote can't benefit from a demutualization effort then it forces would-be carpetbaggers to plot this implausibly long game where they all agree to join in, say, January 2017 and then vote to tear the society to pieces in February 2027 having now all met the ten year rule. But in reality in 2026 when you send those "Everybody ready?" notes around to remind them of what to do in 2027 you'll find a bunch of your fellow plotters got money trouble meanwhile and had to quit, or found Jesus and changed their minds or died, or whatever else and so this plan falls apart.

Edited:: Also, I remember voting (as a young adult) against this because it's obvious what happens next. We didn't find out later, the usual idiots claimed they didn't know what would happen because admitting that they knew and did it anyway makes it obvious just how stupid they are.