I actually doubt that happening. Nextbos and PS5 are launching holidays 2020, so most of the year goes on pretty normal. Switch now has in the second half of the year 2019 a lot of releases and with Animal Crossing that goes on into 2020. So the library 2020 is pretty great. If Switch is dropping in 2020 it will not be because of the other consoles. Similar to PS4 not really have been impacted by the Switch. Switch release impacted Vita and 3DS, but PS4 stayed it's course. In the same way I think Switch will be not influenced much by the others. At least at first. Later on in 2021 and 2022 bigger next gen games will come to these platforms, which will not hit Switch. At that time Switch may start to look old.

Come on, they ported 1 Wii U game and it was released early january, ever since they only announce new games, you can't say "it's still going on"

I'm pretty sure Pokemon releases this year and not next year.

The Switch will continue momentum for a while yet. Pending on when BotW2 lands, 2020 could easily be the peak year. However Pokemon in 2019 will make it a hard year to beat, so I still have my doubts that 2019 won't be the peak sales year instead.

When the new consoles drop, there will not be as big of an impact that many want to speculate. Switch is the only console that offers portability so those that are looking for that will still flock to it. Not to mention we have yet to see any hardware revisions, which will also boost sales. Thats not to say Switch will be unaffected entirely, but it will still easily cross 100mil LTS.

While Nintendo is usually great with showing off games only months (and no more than a year) away, Zelda I think tends to be a longer term. Botw and Skyward Sword were revealed years before releasing, if I remember correctly? So I wouldn't assume the sequel to be 2020, but rather, 2021.

To be fair there will probably be one this year, next year and every year. There hasn't been a yearly gap since 2015.

I just realised Animal Crossing actually still releases this fiscal year, just at the tale end of it. But it hasn't been since 2017 that Nintendo had one of their major 1st party titles release in the first half of the year.

I'll need to see the line-up before I guess about 2020. Switch still hasn't received a price cut after all or a hardware revision so who knows very possible.

I to think 2020 will be the peak selling year of the Switch.

The new twins will release late 2020 so PS4 and XB1 will continue to decline over the year, which will leave Nintendo as the lone manufacturer to really pushing it's current machine for the majority of the year, people will probably buy a Switch over PS4/XB1 next year, even more so next year than this. Further, continued first party support and continued increasing third party support and the likelyhood of new Switch models and possibly pricecupts will help as well.

Possible, especially that Animal crossing is coming out pretty much the very last day of this FY. Combined with all the other stuff we'll get (certainly another Pokemon title, for starters, Bayonetta 3 most probably, and the rest will will slowly get announced over the next months and year)

Switch launch didn't hinder the PS4 to get it's best year. So that's pretty much debunked. Especially if they would do as well as the PS3 announcement...

Also, their launch is at the tail end of the year, and as such, not going to hinder Nintendo sales very much for the yearly sales.

In terms of software, Pokemon Gen 8 is their last big bullet left, since Zelda, Mario, Smash and Mario Kart are already available on the system. Of course we can see successors of the titles (except of Smash), but the impact on hardware won't be that much anymore. In 2020 and future, hardware will mainly be sold through price cuts and hardware revisions instead of new software.
Very difficult to predict the peak because of changing circumstances. If the new hardware revisions fly off the shelves like the DSlite, everything is possible the next years.

 Don't released Animal Crossing neither 2d full fledge Mario Bros. 

One AAA 2D Mario bros. maybe rise 20 M  sales