Most blocks now include sub 1sat/vB transactions
If you survey your mempool, or @wiz's mempool, you will see that since block 905,000 or so, there have been many more blocks with transactions that had sub 1 sat/vB fee rates. In the hundreds of thousands of blocks before this trend, 1 sat/vB was consistently the floor of the fee market. Often, you can find blocks that are not entirely full with a minimum fee-rate of 1 sat/vB.
In the first few hundred thousand blocks of Bitcoin, when blocks were often empty, sub 1sat/vB was much more common.
Average mining fees per day have dropped to lowest levels since 2011
If you look at the amount of bitcoin miners are earning in fees per day, it is clear that the recent trend of sub 1 sat/vB fee rates has reduced the amount of bitcoin miners are earning in fees. So much so that there are articles being published about how miners are seeing low levels of fee-revenue not seen since 2011 (#1194581).
If you look at it in dollar terms, miners aren't doing so poorly, but fee revenue certainly isn't at all time highs.
Bitcoin hash rate is at all-time highs
Yet, if you look at a chart of Bitcoin difficulty adjustments, it is up and to the right. Recently, we have seen all time highs in difficulty levels. To me, this implies that miners are able to make a profit mining Bitcoin -- if it wasn't, we would see hash rate leaving the network and difficulty adjusting down.
None of this takes into account the block reward, which is probably incentivizing people to mine bitcoin even though there isn't enough fee revenue to sustain so much hash rate. However, I think we can ignore this for now, because the blocks are going to get found every 10 minutes on average and the block reward is going to continue to be what it is until the next halving. If it's subsidizing cheap block space, no reason I should have to pay 1 sat/vB when I can enjoy 0.2 sats/vB.
One might also argue that mining is being subsidized by governments or investors (if people have a strong belief that the dollar-price of bitcoin will be much higher in the future, they might be willing to mine at a loss now in order to acquire bitcoin...although I don't know why they wouldn't just buy it if they were so convicted).
minRelayTxFee
as a minimum cost for the network to forward a transaction. When theminRelayTxFee
was reduced recently, also theincrementalRelayTxFee
was reduced, as it doesn’t make much difference whether you are sending a new transaction or use bandwidth to replace an existing transaction with an updated version of it. In the upcoming Bitcoin Core 30.0 release, they will both be0.1 s/vB
which means that you will need to pay at least 20 sats for the 200 vB transaction from your example for it to be relayed, and if you were to bump it, a replacement of the same size would need to increase the fee by at least 20 sats to be forwarded by nodes.minRelayTxFee
andincrementalRelayFee
by a factor ten to 0.1 s/vB.incrementalRelayFee
and so I had to look it up and of course I found an excellent explanation on Stack Exchange.