It's not me it's CK:
Now that solo ckpool has mined a block with sub 1sat/vB transactions I have data on the reward mined as the result of a low transaction fee period. Of the ~4900 transactions mined in this block, ~3300 were sub 1sat/vB transactions. It took some time to sift through the data of these transactions to determine what the mined fees were. They amounted to ~.0018 BTC more in fees, or ~$220. This is ~.06% of the current 3.125 BTC block reward.
Whole block in question fees were ~0.012 BTC $1,455, so ~ 13% of total fees.
CK compared the transaction fees earned from the sub 1 sat/vByte transactions in their block with the block subsidy of 3.125 BTC. It would be better to compare transaction fees earned from sub 1 sat/vByte transactions with transactions paying +1 sat/vByte. That's a better way because it shows how much you earn from those two individual groups. Based on the numbers CK posted, their block was filled to nearly 70% with transactions paying below 1 sat/vByte. Probably that's where most of the fees came from as well.
But even if that wasn't the case. Why leave $200 worth of BTC in the air and not pocket it when we know where bitcoin is heading in the long-term?