Theymos has a history of wanting to keep transactions denominated in terms of bitcoin, rather than USD. He kept your treasurer agreement in place for years after the bitcoin price made the fee excessive. Theymos also cannot unilaterally change the terms of the treasurer agreement. If he wanted to reduce the fee paid to treasurers, he would need to get the treasurers to agree to a new rate, and risk that some may not agree, and be left with fewer treasurers
I'm sure most would understand adjusting the new rate, and if they aren't then I'm sure adequate replacements could be sought after. Although, theymos has stuck with Bitcoin denominations rather than USD, it might be time to consider tying it to something which is a little less volatile. I'm not sure the best approach to be honest, but I'm sure there will come a time where an adjustment will be made.
Although, theymos sticking to Bitcoin denominations isn't always valid. There are instances unrelated to treasurers where its tied to USD value.
Yea, I am sure that most treasurers would be willing to take a pay cut (assuming they are paid what has already accrued, but remains unpaid), and to tie the pay to USD.
It is however fairly standard for the cost of escrowing to be a function of the amount being held in escrow, although as the amounts to go, the rates tend to go down. Coinbase
charges .5% per year to maintain custody of bitcoin, and I would think this would be the lower bound of what an escrow provider would charge for large amounts. The four treasurers are collectively receiving 3
BTC per year and are holding 500
BTC, so they are collectively charging 0.6%.