Well because in the example i gave you this decreases the miner's reward. The rule of increasing feerate you stated isn't always economically rationale.
> It's not that simple. As a miner, if i have less than 1vMB of transactions in my mempool. I don't want a 10sats/vb transaction paying 100000sats by a 100sats/vb transaction paying only 10000sats.I don't understand why the "<1vMB in the mempool" case is even worth consideration because the miner will just include the entire mempool in the next block regardless of feerate.