Vig no longer gets early access.
Mike Boozer Customer Service & Event Team Manager Gen Con LLC
Boardgamegeek has started a pre-order system in their Gen Con preview:
https://boardgamegeek.com/geekpreview/13/gen-con-2019-preview
Publishers can take pre-orders from you through the BGG preview page. You pay for the game now, and pick it up at the convention booth. They started this system at Origins this year, and it worked out well enough that they're making it available for Gen Con.
Not all publishers are participating -- right now, there are 146 titles available, all of them board games. (Sorry, no Pathfinder 2.0.)