People are social creatures and get influenced socially: it’s not always effective to just tell someone about something, they have to know that some other people they know are into it and that they may be missing out.
Discussion
I think content is a sort of issue. It's been mentioned a few times, the casual user will find it hard to find the pockets of interesting content. Not sure how many would stay for a feed of 'fix the money fix the world' for eg lol. However the strength really of nostr (and which I actually sadly can't participate in) is the ability to build and projects to work / join in on. I think that could be a potential angle imo. But yes again, I agree it would take an influencer/someone with a following to get that word out effectively. Just think out loud.
This is not meant to sound like a dig at anyone fyi, lol. It's said with the hope that nostr succeeds:)