A couple of months ago I really thought FF7 and Animal Crossing were games of similar sales caliber. I thought sales were going to be close with Animal Crossing having a bit of an advantage. According to Wikipedia, "by the end of 2005, [Final Fantasy 7] had sold 9.8 million copies worldwide, including 4 million sales in Japan and 5.8 million sales abroad in North America and Europe." And that was on the PS1 alone. The best selling Animal Crossing previously was Wild World, and VGChartz has it sold 5.3m in Japan and 12.1m worldwide. Considering FF7 had been released on other platforms I really saw these games as close in sales.
This is not close. Not by a long shot. At this point, FF7R would do well to sell half of what New Horizons does in Japan. I doubt it will even do that. I doubt it will even sell a fourth of what New Horizons does in Japan. Animal Crossing is already so far ahead with only a -2% WoW drop while FF7R has a -90% drop. There is no catching up. One might even think that this virus would make it easier to play a home console game, since so many people are stuck at home. It helps but not much. FF7 and Animal Crossing are not close anymore, at least not in Japan. New Horizons is shooting ahead while FF7R is falling behind.
It was never going to be that close, especially in Japan. Trying to predict sales based on the original which launched over two decades ago doesn't work. Much different market these days. In particular the Final Fantasy franchise is not nearly as big as it used to be, while the PS4's market is significantly smaller than PS1's.
Meanwhile, Switch games have generally been selling much higher than than games launched on the 3DS, and New Leaf's official numbers I think are about 12 million from Nintendo... and it's still actually selling a bit. 5.75 million of those are in Japan, so even if New Horizons just held that number and didn't beat New Leaf it would comfortably beat FFVII.
Ten million was basically the maximum for FFVII and the minimum for Animal Crossing. JRPG is just a far smaller market.