Well I think they could with some help at the beginning, the question would be more like, why would they? if their npub basically already comes with an ecash wallet.
L2s like ark and spark that use trustless swaps onto the lightning network will do the job. They won't need a custodial solution. Also, they'll probably just use paypal.
Explain further please. I was just today thinking that the openclawification is going to cause a boom in VPS's and create a much easier entry point for lightning nodes.
You know a lot more about this than us so please give us the reasons why you feel this way.