I think voting for anything is full of flaws, we can see that in political elections all the time.
Maybe we should have random pizza winners selected next time, after we first vote for worst pizza designs that should be eliminated

I kind of like some variation of this randomness idea.. but instead of eliminating the worst pizzas.. to allow for some counting (some weight) to the votes, so maybe the first stage would be to merely eliminate somewhere around half of the pizzas (or maybe 2/3rds or some other reasonable number?), so in this case half would be around 70 pizzas or 1/3 would be around 47 pizzas... .. So then maybe the second stage ends up with randomness or even picking out 10 pizzas.. so then the financial reward ends up getting spread out more..
I don't know.. but I like the generation of randomness if there is no real meaningful way to sort out the voting collusion problem.
What of making the voting on the firsts stages to the discretion of a selected jury.. first stage for nominating qualifyed pizzas and second to jury voting to keem about 10 or 20 pizzas for exemple ! Then for the final stage open the voting to everyone ??