Holy wall of text... :D
those that I have supported the most have been the ones that have remained so I'm happy how that turned out.
I am one of those and I am thankful and I think there are people that are still pushing here because of me too now... mostly my shilling ;)
So what I'd tell new people is get to know others, become friends, if they share the same goals as you here then being more friendly with curation is great cause you'll always be around and distributing the reward pool together.
This is what I am hoping the new buyers and decent earners are going to keep doing and slowly bring more into the fold.
Those who earn Steem easily and don't believe in it's long term existence are those that easily sell it and like you said, now find themselves having a hard time getting that stake back from the pool.
It is a shame ;D