It's very realistic. But it will be a decade before the education + awareness is good enough... for people to actually start using Lightning.

Outside of some relatively hard-core Bitcoin communities noone has even heard of it

You mean email spam?

I use it on my personal email server (self hosted, own domain, self managed), configuring the spam lists in such way that only whitelisted domains/addresses are allowed to send me emails. All the rest are banned and will receive a NDR (non delivery report) that can be configured with a special message explaining that if they pay a certain amount to a specified LNURL they will get white listed and their emails will be read.

But anyways, the best way to fight spam is to avoid it, as I explained in this guide. Use aliases for each bullshit account online and if you start getting spam, just delete the alias.

Compartmentalize! Use a personal email domain ONLY for personal stuff. Use a throwaway email domain/account for all the rest of the crap you are doing on internet!