Are you suggesting that I'd pay $20 to move $10,000, and only $0.002 to move $1?
The problem I see with this is that I suspect it won't be possible to enforce this 0.2% fee structure. The reason is that from the miner's perspective, it costs him the same amount to produce a kilobyte of block space whether he uses it to record the $10,000 transfer or the $1 transfer. This means that a miner would make a huge profit on the large transfer and perhaps even lose money on the small transfer. How would you stop miners from undercutting each other? For example, I would be happy to include the $10,000 transaction in my block for $10 (rather than $20) because my profit margin for that TX would still be huge.
Exactly. It costs almost the same network/cpu resource to confirm a 100 bitcoin transaction or a 0.1 bitcoin transaction
If miners charge same fee to all transactions, then the fee will be extremely generous for those rich guys/institutions doing large transactions if the fee can also be accepted by casual users doing micro transactions
The decision of including a transaction is totally up to each miner. Even the block space is more than enough, a miner would still be motivated to exclude a transaction without fee, to reduce the chance of his block being orphaned
I remember that you have some reseach about the market behavior of fee setting, it says that supply and demand will find its balance
Miners might compete for a lower fee, but I don't think this vicious competition will last too long. Major miners will eventually reach some kind of consensus to promote an enough high fee to maximize their profitability, while still satisfy most of the users
For example, if they observed that majority of the transactions are larger than 0.1 bitcoin, then they will promote a minimum fee of 0.0005 bitcoin to not disturb the majority of the users and at the same time greatly increase their mining income
Of course, a small mining farm might include all the transactions with <0.0005 fee, but since his blocks are only mined every 24 hours, his block will always be full, have higher risk of being orphaned, and with very little fee income. Why should he do that? From user point of view, any fee less than 0.0005 bitcoin will take more than 24 hours to confirm, so they will just raise the fee to get a faster confirm. Confirm in time is much more important than fee