Recently, I've seen people discuss whether the ecosystem will move after a major public chain upgrade or downtime... I instead think: if you're really going to do a cross-chain transfer, who do you trust?

IBC, which looks like a "native" message passing protocol, still fundamentally relies on light client verification and consensus validation on both chains;
many bridges are more like trusting a set of relays/multisigs/validators, plus frontend and routing, and any failure in one part could turn the "transferred assets" into an IOU.
To put it simply, cross-chain isn't just clicking a button; it's spreading trust from the chain into a series of components.
As for what I mean by "long-term," probably on a quarterly basis: a week or two of excitement doesn't count,
only those that can withstand two upgrades and a liquidity drain and still remain stable are truly reliable.