collator-selection pallet. i notice that when distribute the reward to the collator, the reward is the half of pallet account. why does it not distribute all the balance of pallet account? if take this, is that mean the next collator can get more reward? i'm confused about it.
It does increase the reward for the next collators, but there is an economic problem with giving all fees to the block author. The fees adjust per-block according to the
NextFeeMultiplier, which adjusts based on how full (in weight terms) a block is. So if a block is empty, then the fees for the next block are lower, but if a block is full then they are higher.
If a collator takes all the transaction fees, they would actually have the incentive to stuff blocks with thousands of their own transactions (e.g. balance transfer from
my_account_B), because it would make all future transaction fees higher, and they'd get their own fees back as the block author.
However, if 50% of the fees go to some future collator, then collators would lose funds with this strategy because they'd only recuperate 50% of the fees they were paying.