I'd happily make a monetary bet right now that Prime will easily sell the bulk of its sales within the first 6 months, nothing you just said makes any difference, especially with your point on 'it sold well so they dropped the price', that's literally not how the process works for dropping prices with Nintendo outside of it meeting some arbitrary number to be labeled as a players choice. You drop prices because the game is not selling much at the current price and you want to drive unit sales, by the time Prime 2 came out and cratered the system was basically headed towards the graveyard so they likely saw no purpose in trying further.
You can also bring up Prime 3 if you like, critically acclaimed, huge selling console, sold most of its bulk immediately, cratered shortly after. You also simply ignored Dread which also came out, sold a few million instantly, it had people going 'omg will Dread sell 6 million!?' because they assumed with such a strong start, it would keep going, especially since the reception for it was very strong.
It did not, it's still likely on the low end of 3 million, we might never see it reported again by Nintendo using their 'sold a million more units' metric.
Prime 1 was an anomaly for this series, Nintendo tried to position it as THE game for the system, it was among the biggest single pushes they tried for the Gamecube, likely to try and counteract their 'kiddy' image of the time, and it sold well immediately and entered discount territory later, something that isn't going to happen with Prime 1 Remastered. They will likely never formally drop the price of that game unless they introduce some kind of players choice line for the Switch, and even then, I'd not count on it.