No problem, yes some way to reward evergreen content would be handy like you say. Although I am likely the; have an idea, write an idea, print mentality of writing for now. I feel its making me less precious with what I write.
Ha yes, I remember that series of Torchwood, that was super dark (also the children being drugs one before that was pretty heavy from memory). Yes, that would be terrifying but the pushing healthy life forward would be very different, especial if we start with the low hanging fruit (e.g. malaria/infectious diseases). I think your right, social change would slow down as the main pushes are usually generational like you say. So how about this, you’re allowed to live as long as you like however you have to move with the times, the moment you say ‘kids these days!’ you’re out Logan's Run style. Sound good?
I suspect this would have to be tied to not having kids. Ultimately, the resources would run out.