It would be very stupid for Nintendo to tank their holiday sales for a product that won't be available until 6 months from now or when ever really. They have product to sell in the here and now and a holiday season ahead of them.
I've said it before but in today's day and age, announcing hardware 6+ months in advance is just stupid unless your existing hardware is basically dead like the Wii U was and even then Nintendo really did not start any actual promotion/unveiling for the Switch until just about 4 months ahead of launch, Switch Lite and Switch OLED were also only announced about 3 months prior to launch.
I agree with soundwave here, the only reason why the Switch was announced 8 months before release...because the Wii U was a dead console. There as no hype in the holidays and hardly any new games released during the holiday 2016. It was better move for Nintendo to prepare and create hype for the switch. Since the Switch has become a huge success, it wouldn't make sense for the switch 2 (there will not be a pro) to be announced before the holiday season. If the Switch 2 was announced...you're effectively killing switch sales. It would make more sense for an announcement to be during the end of the holiday season like late December or early January.
People tend to forget we live in a modern day, we don't need announcements years before a launch of a device anymore. Social media has made advertising easier to reach the masses compared to prior methods of advertisement. Things can go viral worldwide within minutes of an announcements. Advertisements, videos, presentations, and so on can reach the masses compared to 20+ years ago when a commercial will take time to even reach syndication or even putting ad in the paper/magazine used to take time. Now all it takes to post an ad on facebook, twitter, youtube or other internet platform is a click of a button (just simplifying the process). This is why we have seen releases of some devices happen within 6months rather than announcing a product that will release in 1 to 1.5 years.