Sure, buying Nintendo would be a win for Microsoft, but Nintendo would gain absolutely nothing from the deal. Sure, there are people like myself who loudly and rightfully complain about Nintendo's business practices, but at the end of the day, it took until THIS year for Playstation 5 to finally outsell them in a single year, and they're not even CLOSE to matching total unit sales, and Xbox is doing worse than THAT. Add to that Nintendo's software attach rate, and as much as I don't like HOW they do their business, they're WILDLY successful at it and making more money as a function of their costs than anyone else in the industry, so they can't be faulted for continuing to do what is working.
I honestly don't know what Phil Spencer thinks would be different than the previous meeting in another sales proposal today, especially given Microsoft's INCREDIBLY weakened industry market position compared to Nintendo's. Microsoft is only able to approach the idea from a position of power based on its market capitalization funded by its other businesses - in the gaming industry, Nintendo simply occupies the more advantageous market position.