It will all depend on the install base. Either way, rival companies better not even attempt to launch a major IP during its release window because it will incinerate it whole.

20 mil

I don't think a single game will determine a system's peak year on it's own, we need to know other factors like what other games released, if there's a price cut, and so ons. 2013 is when X/Y released yet that's not the peak year for 3DS, infact 3DS never really had a peak year, sold about the same for it's first 3 years then went downhill from there.

If the Switch is out for 7 years or more, than it will max out at 25 million peak year. If the Switch is a regular 6 year console, it will max out at 30 million peak year. This is because I want my prediction to come true so I have to cover my tracks and weak spots to be right.

I think the first generation of Pokemon on the Switch won't be the system's peak year. If any year where a Pokemon game comes out was to be the peak year, it will probably be the year we get a 2nd Pokemon title on Switch.

I think I forgot to explain myself a little bit ... 

I think there's some info out there (?) that Nintendo consoles often hit their peak in their 2nd year (very early!) or third year (somewhat almost normal). I can't remember if that's mostly exclusive to their home consoles(I think it is for the most part), I haven't looked in a while, but that would make sense. I think though, that there's a lot to consider with the Switch. This year, we probably won't get any price cuts or new models. We might see special price cuts at select retailers in certain locations only, but that would probably be only during black friday and it probably wouldn't be something Nintendo would heavily advertise. So the Switch is still going to be 300$ with no other models out there. 

If a Pokemon game comes out this year, then there's a chance the next game in the series will come out during a period where the Switch has at least two different models, probably at least one significant price cut, and it will probably launch the same year as the next Mario Kart. 

Honestly this all gets very confusing because it has a lot to do with what Pokemon game is coming out (remake vs new) and when ALL of the Pokemon games come out in the first place. If the first Pokemon game comes out holiday next year ... I could see next year being the peak, too. I think though, even if Pokemon Switch 1 comes out this year, it won't be the peak year.

A Pokémon release will help delay the impending, and inevitable depression of the US economy for a short period of time.

15-19m i think is a lock

If Pokémon releases by the end of this year, they can definitely reach their goal of 20 million.

Are Pokemon games for the Switch gonna be released annually this generation? It's very difficult for a game with an annual release to reach 30 million

2018 won't be the peak, whether Pokemon releases or not.