Tim Swanson thinks transactions cost 25 BTC divided by the number of transactions in a block. That's a complete misunderstanding of not just what the block reward does but of what Bitcoin even is. He has gathered some interesting data, but his analysis is unlikely to be of much use as he has no fundamental understanding of Bitcoin in the first place.
Tim Swanson (who understands bitcoin's economy much better than most bitcoin gurus) is looking at the miners as an entity that performs a service to the "bitcoin system" (validating and securing transactions) in return for a payment (the block rewards and transaction fees).
Right now, that entity gets 25 BTC (~6000 USD) for each validated block, and the average block contains 750 transactions. So the miners are being paid ~8 USD for each transaction that they process, on average.
In percentage terms, the transactions in a block move about 280'000 USD, on average (excluding presumed "return change" outputs); so the miners' revenue is about 2% of the money that they move.
There is not much room for misunderstanding there. Right now, the bitcoin network is way too expensive for the service that it renders. If the price were to rise to 2'400 $/BTC before the next halving, and the volume numbers doubled until then (which is what they barely did over the last 2 years), the miners would be paid ~40 dollars per transaction , or 10% of the transaction amount, on the average.
As you all know, those 8 bucks (or 40 bucks) come entirely from the pockets of new investors -- the people who are buying bitcoins today to increase their holdings. For the price to increase to 2'400 $/BTC over the next year, there would have to be a 10x increase in the money brought in by those investors. I hope that everybody here is aware of that.
The money earned by the miners will never get back to the system; therefore, the only hope that those new investors have of recovering their money is that there will be enough new investors' money coming in tomorrow to pay for tomorrow's mining
and to buy those bitcoins that they are buying today, hpefully with some premium.
Thus, at current prices and rewards, the bitcoin protocol is creating every day another million dollars of naked debt: money which the bitcoin holders have put into the system, and expect to get back from it --- but which has been given to the miners, and will not be returned by them.
By pushing the cost of the network to those new investors, the protocol allows the users and entrepreneurs to entertain the illusion that transactions have almost zero cost, and therefore are cheaper than international bank payments and remittances. This whacky "business model" cannot go on indefinitely.
