[cryptobeanbaby]

  Mining pools form due to the transaction costs of decentralization.

Better explained as a result of the mining protocol being winner takes all, and is granted write access authority (for guessing a increasingly larger random number), that by pooling everyone's lottery tickets together and paying the pool operator, the agree to take a small sum of each successful guess from the pool (assuming the pool fairly pays out participants).

"decentralized" except not.

[darawk]

Variance is a transaction cost.