you can see that jochen-hoenicke retains tx below 20sat/vb because HIS mempool is set at 550MB instead of standard 300
but by seeing the straight line(unnatural) of the 20-21 colours they are purged by majority which means only jochen-hoenicke is retaining them hence the straight line. where most natural transactions of 300mb mempools are purging cheap fees
(if very cheap tx were being added you would see wiggly lines of tx's coming and going as they get relayed in - confirmed out)
In another topic I'm developing, here:
https://bitcointalk.org/index.php?topic=5483213I'm gathering some information about the blocks mined in each difficulty cycle, and that includes the average rates for each block mined.
And it is really interesting to note that in the last cycle, there was no block with an average rate below 50sat/vb.