Ethereum

The major selling point of Ethereum is it is more decentralized and more secure than others.  And chains that optimise for scale are disparaged ("Sqlana!").

Yet to scale we have accepted the L2 approach, and therefore, significantly in most cases currently, lower security.

Are Solana type trade offs acceptable now?

Enthusiastic about web3 domains. Imported a web2 DNS address into ENS and voila, got my grail domain, Jack.top

For that L2, but not Ethereum base. And there are many L2s, which is a desirable consequence of decentralization. Can you explain how the L2 approach has lowered Ethereum L1 security?

Well the expectation/goal is for majority of users to be transacting on L2's. And L2's by their nature will not be as secure as ethereum. So in order to scale, there is an inherent acceptance that security is reduced for most ppl. At which point, does ethereum the ecosystem truly remain more secure than an alt L1?

I think you absolutely have to take into account the ethereum ecosystem as a whole, because it is trying to achieve the dame goal as a monolithic L1.

If all the users are using an L2, then they receive the security of that L2, not the eth L1 for those users it doesn't matter if L1 is more secure.

The slight of hand is comparing the "Ethereum ecosystem" to an alt L1. Sure, distinct, non-essential parts of the system enjoy security tradeoffs, but L1 remains secure. Whereas Solana L1 is affected by these security compromises directly and intentionally.  

So, yes, Ethereum L1 truly remains secure.