Keep in mind Itch.io does not have a ready market of players willing to snap up every game.
With your early-access scheme, unless you have a strong network or following elsewhere that you can bring over to itch.io - you're unlikely to sell much (if anything at all). This is a reality for many of us developers. Our games just get lost in the ocean of games. Having a partially made game might make it even more difficult for you to get players' attentions (or money).