Humm interesting question.
I believe the sprite and intent is to allow developers to fund their development through secondary means by association so personally I feel it would be fair to introduce a perk at a lower price point, and pay royalties at that price point, even though it sounds like an end run around paying the higher fee.
Seems logical, and a win win for both parties, to allow early access far below what the game would normally sell for, and pay fees on, that would help the developer pay the fix costs of what it takes to bring a game to market.
What I don’t like is middlemen getting into the mix as in my experience it never ends well and are general motivated by other reasons besides making the best game ever and crowd funding in general is a one shot deal and with Kickstarter you either get or don’t get the funds which opens it up to abuse.
The marketplace on the other hand opens up a few possibilities if done right and does not once again turn into another bit bucket of junk.