I kinda think it's possible for a short while.

Ethereum is not good money. Ethereum is a shitcoin casino. But it's possible that markets will temporarily value the latter more than the former, because markets are dumb and misprice things. Especially if you combine bull-market euphoria with Ethereum's illiquid supply (pre-mine + staking).

So while I don't expect it, I also don't rule out a temporary flip. It doesn't matter in the long run because Ethereum has several complementary centralizing pressures that, best I can tell, are rather insurmountable and will result in the downfall of the protocol over the long run.

Besides, market cap is a highly flawed metric and easily gamed. I don't particularly care if Bitcoin gets flipped. It's still the soundest money we have.