That's because, after more than 2 years, the defining feature of Switch is arguably its library, and its ancillary features, which have over the last two years done enough off the back of their novelty to help put the Switch into homes worldwide, can now be relegated to well-understood novelties that consumers can now decide whether or not are valuable enough to them.
As I said earlier, it's not March 2017. People aren't buying the Switch today to see those controllers in action. They're buying the Switch today to play Pokemon, Odyssey, Mario Kart, Zelda, and other games. That other shit sits secondary, as is the case for almost every years-old platform under the sun. And if that stuff is not secondary to a given customer, then they can still choose to purchase the Switch that can be docked.
All in all, this just gives Nintendo the opportunity to sell the Switch to a wider range of people. Now, people who weren't interested in Switch as a console or who didn't want the Switch at $300 don't have those barrier sitting between them and Nintendo's games.
And the same will be true when Nintendo inevitably reveals a tiny, inexpensive, TV-only Switch in the future, for those people who aren't interested in handheld gaming, but who still want to play Switch games.