Obviously, as it's the series that put Cloudhead on the map before Pistol Whip, they haven't forgotten about The Gallery; they just want to do it justice.
In the Reddit AMA, a company representative explained:
"The Gallery holds a really special place in our hearts and of course we would love to return to it at some point–but we really do need the market to be bigger first. The way I see it, the next time there's a massive innovation in VR, the same way roomscale and hand tracking reinvented the medium, EP3 would make the perfect candidate as a 'next-gen experience."