Can someone help me to clear my doubts about the need of an L2?

I’ve read that the future of Ethereum is with executing transactions on L2. Rollups like zkRollups are presumed to be the future. I totally get how Rollups and side chains are needed to alleviate the Ethereum L1. But I also wonder if the need to have an L2 is simply because of the limitations of the current version of Ethereum?

Bridging between L1 and L2 is troublesome and a lot of anxiety. It’s also less simple since a particular token can be on L2 sometimes it isn’t. The experience isn’t the best though we still use it out of necessity.

Some blockchains such as Solana try to make their main chain capable of processing transactions without the need of any L2. This makes things simpler.

A few questions on my mind: * Are L2s only needed for any particular blockchain because of the cost and transaction limitations of its main chain? * Does it mean an L2 is not necessary at all if the main chain could handle all of the transactions at a low cost and speed? * Other than Ethereum’s current user mass, what is preventing blockchains that are capable of executing everything on its main chain without the trouble of L2s replacing Ethereum since it’s more convenient? * Even with ETH 2.0, when it has been merged, as far as I understood (which I could be wrong), L2 Rollups (be it optimistic or zk) are still needed, is that right? Then what’s the deal here about the scaling if an L2 is still needed in ETH2 other than the change of consensus?

Thank you for any help to clear my doubts!