Here is a question I have. What is the top selling game in Japan by revenue? It might actually be AC: NH at this point (once you include digital). It's selling for about 6000 yen. I'm pretty sure every other game in the top ten had a significantly lower price. Also inflation isn't much of a factor in Japan since it's also had plenty of years of deflation.
Its a good question, considering there is also digital revenue where retailers don't get a cut, also there is potentially new NSO Subscribers.
It's very likely already more profitable than Pokemon Red, Blue, Green and Yellow. Adjusted for inflation Pokemon Red, Blue and Green are actually one of the most expensive games ever launched on a handheld and apparently in the top 20 of the most expensive games ever made. Development actually took 6 years, Yellow was launched in 1998 and the games had legs until Gold / Silver released in 2000
1996 Pokémon Red / Green / Blue - 1.663.861
1997 Pokémon Red / Green / Blue - 3.995.992
1998 Pokémon Red / Green / Blue - 1.520.428
1999 Pokémon Red / Green / Blue - 726.524
Pokémon Red / Green / Blue TOTAL: 7.906.805
1998 Pokemon Yellow - 1.482.638
1998 Pokemon Yellow - 272.142
Yellow TOTAL: 1.754.780
With little doubt that it will sell over 9.66M in the first four years on the market, New Horizon is already probably the most profitable game for Nintendo in Japan of all time. The main difference is that Pokemon also exploded in terms of merchandise, TV syndication, movies, card games, etc.
So although New Horizon is the most profitable game it's still not a cultural phenomenon outside of Japan. There is also a little mobile game that will probably stick around but it's not bringing the type of money selling TV or movie rights might bring to Nintendo.
The main thing that should not be understated with New Horizon is the expansions in terms of demographics buying the Switch. A lot of the new owners would not have bought the Switch without it - every title they purchase on the Switch is an additional amount Nintendo wasn't making before New Horizon launched.