Layer 2 Blockchains – How to Read Events in Polygon, Arbitrum, and zkSync

Ethereum private keys and accounts (addresses) are the same across different Ethereum Virtual Machine (EVM) based blockchains. You can make a wallet work in another network by simply switching the Web3 provider to point to a different JSON-RPC endpoint. All JSON-RPC providers have copied the original Ethereum API.

(Note: Rootstock RSK is a notable difference as they are using a different checksum method)

Now this is just my speculation, but I don't think L2s will disappear. There is no way to get all three components right of the blockchain trilemma: security, decentralization and scalability. Ethereum is pretty good currently on the two first, but the last one is lacking.

To scale Ethereum you either have to go to L2 or try to improve L1 somehow. Yes, there are lots of plans on how to make L1 better (such as sharding), but I don't think any one them can get close to the required levels.

I believe L1 will mostly remain as a good source of security and decentralization. Different L2s then add more various features - one of them being scalability.

L2s don't offer just scalability, though. They can offer also stuff like privacy (for example Aztec) or aggregate transactions (for scalability purposes or something else).

P.S. I strongly disagree with the terminology of "what if Vitalik....". There are hundreds or thousands of people working on making Ethereum better. Furthemore, the term "Eth 2.0" is obsolete.