why can't there be a rolling-30 day payout for upvotes after?
Because our usage statistics indicate that this would account for 0.85% or less of all rewards. Also see my recent blog post "Building Lon Term Value from your Blog" for the real answer to long-term rewards.
Yes, but you are conforming to the current metrics and not the desired end-state.
I have a more detailed post on this concept: Advocating for Long Term Steemit Payouts https://steemit.com/steemit/@mrosenquist/advocating-for-long-term-steemit-payouts