TL;DR: I don’t see any practical path forward for decentralized stuff other than abandon the pretense of cross-chain value transfer and embrace balkanization, while letting the centralized stuff handle the cross-chain value transfer.
I don’t think Polkadot is a path to interop, and I’m still unsure anybody’s at the wheel at Cosmos. Bridges are likely to remain a security mess, given they are a perma-honeypot.
I see two likely paths to cross-chain value transfer:
One is basically no value transfer, other than USDC or stablecoins. Want to move stuff from your Cosmos thingie to Solana? Good. Cash out and use whatever easy transfer Circle provides (or “bridge” through an exchange).
The other is zkp-signed UTXO’s, a la Aleo / Penumbra, stored externally in some neutral layer, which the other side then decides if to honor and how. Effectively, going back to the “company scrip” approach to money. zkps are in the end nothing but a cryptographic signature, so it’s up to the receiver to decide if they trust it.
You could in theory prove the whole source environment, proving effectively that this is a a valid state transition across environments.
That’s fair. But if that “whole environment” is the fact that you held X amount of TUSD on Tron, other chains may not want to trust the source.
Centralized stuff like USDC becomes the closest thing to legal tender, while for decentralized stuff everything becomes zkps and everyone decides if they think any particular source has any value.
And we stop pretending that cross-chain value transfer 1-1 is a thing.
(Update: Teemu and I discussed this more on The Spelunking Podcast Ep. 21 when we were discussing a “zero-knowledge everything” world.)