Ecash is "a fix to custodians", so saying Monero will need ecash is like saying Monero will need custodians, someone to hold other people's keys, maybe Monero will need L2s like Lightning for micro payments like you say but Monero has the ability to scale so that everyone can hold their own keys and create transactions, open channels, so there will never be a need to give away custody
Discussion
No blockchain scales to micro payments. Lightning needs liquidity, which makes one off micro payments difficult. Although, moneros scalability helps the cost of opening channels.
I think both of you make good points, but there are other L2s that exist besides lightning/ecash, and potential future ones we just aren't aware of yet, that still preserve self-custody that we could use on Monero if necessary