The L2 farming process you described is pretty brutal, but there's a lot of truth to that. I also agree that we need to build a shared standard for all rollups. Otherwise, we end up in walled gardens, just bigger ones than the ones we have now: Optimism -> Superchain, zkSync -> Elastic Chain, etc. From the incentives POV, I don't think L2s are prone to do it because more successful ecosystems could lose their share of the pie and the strategic advantage. I think this cross-rollup communication should be eventually built into Mainnet.
Yes - L2 ecosystems’ cross communication should be something to optimize even more, but not the standard / basic way. I could also see ‘enshrined’ L1 <> L2 communication a Frankenstein of all the current proposals from Superchain, ZKSync etc. and that would be good. But still, I guess that this is a few years away: every Rollup has slightly different rules (see: withdrawal periods) and we could only make this work if the primary assumption that the state is what you read is true. Otherwise we risk the cross-chain nightmare: multi-chain reorgs!