yes, Base and USDC are built on Ethereum.

but does this mean the ticker is $ETH or the ticker is $COIN over the long term?

Base plans to achieve Stage 1 decentralization this year:

Bitcoin research and analysis | As seen in Forbes Fortune Bloomberg WIRED BitcoinMagazine

Base plans to achieve Stage 1 decentralization this year: https://base.mirror.xyz/gFOLgyrs8jtX4Eqt4Kh6ikWhB3tqrhQoKfddeqZIECs

Head of Product at @syky /digital-fashion. Love all dogs and especially my own. ex-Ledger

Seems irrelevant to the point. Coinbase still collects all the sequencer fees once this is activated, no?

For the foreseeable future, yes. But Coinbase would benefit more from a fully decentralized rollup (collecting a smaller slice of an even bigger pie), IMO. The Superchain and Stage 2 decentralization aren't concretely on the roadmap, but I think these things will come reality if we demand it as consumers

if they're also pushing for people to use USDC, what are the benefits of a more decentralized base layer that would be relevant here? what if the centralization of USDC and Base is very user friendly and people aren't demanding use cases that don't reintroduce centralization anyway (as is the case today)?

if anything, it seems crypto has gained more adoption as it has become more centralized, not the other way around.

For the foreseeable future, yes. But Coinbase would benefit more from a fully decentralized rollup (collecting a smaller slice of an even bigger pie), IMO. The Superchain and Stage 2 decentralization aren't concretely on the roadmap, but I think these things will come reality if we demand it as consumers https://docs.optimism.io/superchain/superchain-explainer