Interesting, aside from the annoying doom and gloom posts you see all over the place regarding sales, Matt had mentioned that FF7 Remake was now #2 in lifetime dollar sales across all Final Fantasy releases - only behind FFXV at #1. I believe (I'm using vague details, so I'm probably off) that FF7 Remake sold around (or was estimated) 3 to 3.5 million copies within a week. About 5 months later, Square Enix finally broke silence and released a statement saying it has sold 5 million copies up to that point - then they went silent going forward.
If that's the case, FF7 Remake definitely had some additional legs and the eventual EGS release gave it some life. Mix that in with discounts overtime too. The higher price helps of course in terms of lifetime dollar sales though, but to be #2 at this point was definitely an interesting note.
When you look at that and how FF7 Rebirth is doing, it seems to be following that trend. Aside from not selling as much as one would hope, it's about on par with what one would expect. Regardless of hype or nostalgia, I wouldn't expect any release in the trilogy doing more than a mainline (FFXVI and future ones) release. They were relatively close in terms of sales, but overall FF7 Rebirth is trailing just after a month (Total estimate is around 2 to 2.5 million so far). I think eventually once this releases to other platforms + mix in with discounts/sales + promotions, it'll eventually leg its way up just like FF7 Remake did.
I don't see any impact to the upcoming part 3 either (in terms of budge/changes), they'll likely continue on as normal. Once they wrap up the trilogy, Square Enix will do their usual and take advantage of this trilogy and market it all around (Bundles, Integration for one super collection, upgrades to PS6, etc.).
Could the sales be better? Fuck yeah it could be, especially since the game is really great.
But seeing how FF7 Remake climbed since initial release, I think it'll do just fine after some time. Unless Square Enix announces it during their Quarterly Earnings call, I'm figuring we won't hear anything for another few months - then likely radio silence until they start to market the last part of the trilogy.