I don't believe Nintendo ever mentioning the Switch being its 1 platform going forward, more so that the media and gamers believed it to be because of the portability of the console. Nintendo 3DS was a pillar, just like the Switch, Mobile games, and at a time the Wii U. It's too early to call the Switch a huge success even with it selling out everywhere until its shown the sales of the console has lasting power. Also as seen with at E3 it showed where Nintendo's priorities are, with the Switch taking all the Spotlight and the 3DS relegated to Treehouse events.
As long as the 3DS continues to sell, they will continue to make games for it. Look at how long the PS2 lasted for because of the same reason (it still was selling). Mostly due to its huge user base will games still be created. Until the sales of the console start getting into late-Wii U of maybe a hundred or thousand a week at most. Nintendo will likely continue to make games for it.







