By charging a fee, the ecosystem is disincentivizing arbitration. Arbitration is an incredibly inefficient process compared to block production, so we should try to keep systems as automated as possible. If I were an arbiter and wanted to be paid by inflation, I could submit a bunch of transactions and then a bunch of arbitration requests for those transactions, and then serve my own requests and get paid. If I've lost $100 worth of EOS, I'm definitely willing to put in an arbitration request for 10% or 20% of what I get back. Arbitration works to charge fees for specifically because it is almost exclusively used for transactions of value. Just my thoughts on it.
RE: The State of EOS Governance: ECAF & {{ regarbitrator }}