New models phasing out old models is nothing new for Nintendo, so if that ends up happening it shouldn't be a surprise. Phasing out doesn't mean immediately replacing. It could be something like Premium model comes out in a few months at $350, the upgrades and only $50 more makes it a more attractive alternative to the original so it steals a bunch of the original sales, then after a year Nintendo discontinues the original and drops it to $250 to sell what's on the shelf and drops the premium model to $300, thus completing the phase out.
If it releases at $400 it would just be a longer phase out. Maybe spend a year at current price levels, reaching different customers so not really competing all that directly, then in 2022 premium model drops to $350 and in 2023 original discontinued and premium is set at $300.