Welcome to steemit; you have jumped in the ocean in a big way, as an instant dolphin!

On your question -- There is only so much steem available every day for payouts. If the devs change the payout cutoff from 30 days to never, then existing posts may make a little more over time but new posts may make a little less.

I think others probably do what I do -- if I come across a post I like which is older than 30 days, I check the person's blog and try to find a new post that I would like to up vote. So the person's account is still getting a reward from me that day. Further, I may Follow the person and up vote them on future posts. So older posts act as a sales funnel to get new followers/customers.

I followed you, and I hope your huge investment works out. I do feel that Steemit will work out for all of us!