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 is one of the few widely published that really seems to understand Bitcoin if you ask me. I think his advocacy of so-called permissioned ledgers stems from the premise that decentralization hurts the ability of Bitcoin to integrate into the current legal/regulatory pigeon-holes. I personally don't find that compelling, but that seems to me to be the nut of his argument.
Correct me if I'm wrong.