There you go. Once you introduce dev fees, it is extremely difficult to get rid of them from the protocol, due to founder's greed.
Same as with any cryptocurrency. Not all have this "overtime supply fee" of Z-cash, but all have a hidden "first-to-acquire" tax. Or differently put: A capital appreciation advantage. That's why most developers prefer to create a brand new currency, and not focus on one that is already made, which is ironic if you think of it; open-source software means you don't have to give a solution to the same problem twice.
Monetary policy is what takes the cake. That's why the developers of Ethereum corp haven't defined one yet. Decisions that affect it are made accordingly to the stakeholders' benefits:
As Ethereum is a decentralized network, the Monetary Policy cannot be successfully modified unless there is overwhelming consensus from the aforementioned stakeholders. Ethereum follows an off-chain governance process meaning that any and all decisions on changes to the network happen extra-protocol.
That said, due to natural incentives, Ether's issuance is unlikely to ever increase unless the security of the network is at risk. Additionally, the upcoming Ethereum 2.0 proof-of-stake transition will progressively allow for a drastic reduction of Ether issuance while maintaining the same level of network security.
TL;DR, Ethereum (like most cryptos) is fiat.