It’s quite common for board games on Kickstarter to offer print-at-home files at higher pledge levels. This gives the opportunity for backers to play the game before the rewards are delivered. However those projects don’t just publicly release those downloadable files afterwards - both out of respect to the backers who pledged additional campaign funds to get them, and because the product does have value beyond just the manufacturing cost.
If you think about it most board games are really just simple pieces that could be printed at home, but I doubt you’d have much success just emailing a board game company saying “come on guys, it’s just printed stuff, just give me the files for free”.
By the way the actual ZapBox world markers are nicely printed with a matte foil finish on dense corrugated cardboard, rather than just being printed on paper. The controllers also feature triggers which are not part of the print-at-home kit delivered as part of the Developer Bundle. On top of that you get a high-quality Google Cardboard headset, and the fish-eye lens adapter that offers a wider field of view for the camera and hence more immersion and better tracking.
We think $30 is a very reasonable price for that, and looking at the comments on the Kickstarter page it seems the backers who are receiving their kits now generally agree, despite the still-early state of the ZapBox app.
We have never claimed that ZapBox would be available to print-at-home for free so I fail to see how any accusation of it being a scam could possibly be justified.
Longer-term we haven’t ruled out the possibility of making a free print-at-home version available but no final decisions have been made and certainly it’s unlikely to happen in the next couple of months.