This was originally a big thing for me when I understood I could get payouts for a very limited time. I do understand that new posts kind of deserve the rewards, but still I find myself going through old content and finding a lot of useful and awesome stuff from there.

Should I upvote an authors new post because I thought his old post was awesome and I want to reward it?

Should I ask him to leave a comment, so I can upvote the comment on the old post so he can get a payout for it?

That could actually become a big thing too if someone creates a bot which comments every week to all old posts "Upvotes for week 25 in 2018" and he can get continuous support from people reading the old posts (if it ever happens).

But let's hope SMTs will fix this issue (or "issue") depending on your own viewpoint.