This isnt even a rumourzone, you can work it out through sales stats compared to Dragons Dogma 2. Looks like sales are in the ~2.5 million area.
There are a lot of contributing factors to this. First of all the exclusivity deal was a huge mistake. This should have been on everything and day and date on PC. Even Xbox would have helped, as much as people go but these games only sell a small fraction on Xbox, FFXV sold about 20% of its copies on Xbox and it would definitely be nice to have that extra. These last few games also are the first major Final Fantasies to not release on the leading system at the time (when XIII Wii sold more than PS3 and 360 total but fewer after XIIIs release). In Japan software sales are higher on PC than PS5 and even the install base seems to be catching up. Playstation is a smaller fraction of the market than its almost ever been, you cant support a huge release exclusively on there.
Also to that point, Remake was Epic Game Store exclusive which probably significantly affected its PC sales. Its silly but put it on Steam.
Thats not all though, there are games that have sold better only on PS5. I do think the ties to VII make it a more limited appeal as its not bringing in as many new players as an original title, you can also see this reflected in Remake being down from XV.
Most importantly though the Final Fantasy brand is just in a dire place. XVIs sales werent great either though they were better than this. It has been a long decline really going back over a decade (XV was a spike upwards thanks to PC+Xbox but not in Japan) and in that time it was just poorly received game after poorly received game. Now theyre releasing good games again but not enough people are playing them. What can I say, the series never recovered from XIII!
Its a shame because I would really love a similar project for VI over two games but I dont think that is going to happen now.
I just decided to change this sig.
Blaaaaaaargh
azuarc