Gavin Andresen, one of the earliest bitcoin developers, has stated he is 80% sure ethereum will scale in the next year or three.
Thus solving bitcoin’s scalability problem by “trustlessy tokenizing your BTC,” allowing you to then “transact using the wrapped tokens on the eth2 chain.”
He argues scaling eth and trustlessly tokenizing bitcoin “aren’t actually easy,” but recent developments have made significant advances on both regards and in the present, not in a year or three.
RenBTC is one new project that has launched just this month and claims to have trustlessly tokenized bitcoin into ethereum.
They use an algorithm to keep the bitcoin private key secret from everyone, including ren nodes which anyone can run.
Through an API, and later by incorporating a light wallet for the ren nodes, they can read the relevant parts of the bitcoin blockchain and see if there was a deposit which is then consolidated into the public address of the ren nodes.
Presuming 2/3rd of the nodes agree there was a legitimate deposit, they sign with the Shamir secret like chopped up private key. You can now give this signature to the ethereum smart contract and get your renBTC.
The system is very new and they’re having more audits to ensure all is safe and works as it is meant to work, but if it does then this would be a pretty big breakthrough as it would be a near native bitcoin integration into ethereum.
Because this is a smart contract, scalability is also arguably not a problem now due to numerous new methods that use zk tech or many other new technologies to keep accounts within the smart contract, and then settle on the ethereum blockchain.
So you can have 2,000 renBTC transactions, and then by the smart contract using one sublayer scaling method, you get to have only one transaction on the ethereum blockchain itself.
That means ethereum now has pretty much solved scalability where smart contract based tokens or dapps are concerned, but with all these being very new, it takes some time for integration and implementation.
Hence in a roundabout way bitcoin is also scaling too, with its early bitcoin developer, Gavin Andresen, now seemingly focused on eth.