1. There seemed to be a tidal wave of minimal effort posts made by people who obviously came here just for the "free money" but had zero interest in actually contributing anything valuable to the community.

I just don't upvote those :)

1. When I found a rare gem of a new user, I would comment on their post, upvote them, followed them, etc... only for them never showing up again or making just a couple of posts before quitting, ending up just as some dead number in my following.

That risk is always included - That's why I only try to vote well made introduction posts - Sure it's not granted they stay - But chance's are higher. And there always will be some who quit. That's just the way it is.

I whish there was a way to also increase the quality of new users... is that even possible? Or is this just the way it is?

Support good users and flag spammers + report them to @steemcleaners!