Square Enix has this propensity to announce games years ahead of time, and then not release them due to protracted development cycles- Final Fantasy 12, 13, 15, Kingdom Hearts 3, and Final Fantasy 7 Remake are all but a few games that have suffered this fate.
In spite of this, however, it seems as though development on Final Fantasy 7 Remake may actually be ahead of Kingdom Hearts 3, if only in some regards.
That said, we can only hope that development on both proceeds smoothly now, and they both launch on time, as intended.
The latter two of those games are actually the two biggest games Square currently has in the pipeline- and both are currently languishing in development, even though Square Enix has recently committed to a 2018 release date for Kingdom Hearts 3.