It'll be remade eventually but only as a last resort when things look bad for them.
They will want to hold on to the nostalgia factor as long as they can without actually potentially ruining it through a remake.
What remakes have actually sold close to their original?
There's little motivation for the creative people to re-release something that's already been done when it's just as almost just much work as creating something new, and generally less fun.
The only way I could see them doing it is if maybe, FFXV bombs from a sails standpoint. But there's less pressure at the moment. Their stock price has almost doubled in the last 6 months (mainly since FFXIV's release), and loss was revised to profit for past 6 months.