I remember getting asked a lot in 2021 if zk rollups would "obsolete" optimistic rollups (ORU's). My answer back then was that what matters above all else is building a sustainable ecosystem - which optimistic rollups like Arbitrum One and Base have done - and then later on these ORU's can simply upgrade to become ZKR's. It's very nice to see that my 4+ year old prediction is playing out with this partnership between Succinct and Arbitrum! ZK has always been the endgame for Ethereum.