Odd examples to pick, Horizon Forbidden West and God of War Ragnarok were both delayed and the first original Mario platformer for the switch came out in 2017 (Odyssey - if you think 3d Mario games aren't platformers you haven't played them). Nintendo has also been releasing tons of other games as well so it's not like they've been doing nothing.

Also, to be fair, When you have a platform with 10 times the total sales (Wii U sold ~14m, the switch is at ~130m right now) it makes sense to port over the good games from the console no one owned. Mario Kart 8 deluxe, a game originally from the Wii U, has sold ~55m copies, which is about 4 times what the entire Wii U console sold. There's a reason they kept doing it, and it's because most of the Wii U titles were good games that people will enjoy which released on a dead platform.

If you're going to criticize Nintendo, criticize actually valid things like the scummy price increases on the ports (not just the ports' existence), the poor online system that costs up to $50 per year per account, and a legal team who goes after anyone doing anything that isn't directly playing the game. To be clear, a Microsoft buyout probably wouldn't change any of those things because it's making them money. Look no further than American companies like Disney largely using the same strategies Nintendo does. Microsoft is no different.

To be fair, the Switch has Super Mario Maker 2, which is the definitive 2D Mario platformer. The only real advantage that Wonder has is that the game isn't limited by the items in the game, and the trust that the levels are curated to be good. Otherwise Mario Maker is a superior product. It honestly feels weird to see Wonder being released at all.