Thank goodness for Steam. They saved PC gaming where Microsoft had no real plan of action (or IP outside of Halo) to lure people to live. Even then, they made Halo 3 exclusive to secure their lead over the PS3. See, it was those moments (as you alluded to earlier) when they realized exclusives mattered.

And the games Nintendo put on phones were smaller cost simplified version of the Nintendo IPs. So it certainly is different to compare MS putting their best IP full for switch against Nintendo making taste version of their games on phones. Also it isn't restrict to one platform or devaluating Switch itself.

I'm not talking about putting their flagship Halo games like Infinite on Switch though, I'm talking about the older 6th/7th gen Halos. Nobody is buying an Xbox One to pay those, and you can already play them on other platforms.

Halo MCC have brought many fans to X1.

So why not release the library of WiiU on X1?

Is anyone at this point really still buying Xbox Ones to play the old Halos? I sincerely doubt it.

As a company that only does games, Nintendo is naturally far more dependent on their IPs than MS.

MS has finally realized this gen that the money isnt in the console market anymore. They can make more money without the billions being lost in the console market which isn't rocket science to work that out. They could have easily done another Steam however why would they invest heavy to compete with Steam when Steam already sells Windows for them? I showed you a graph of more than 70% of Steam Users using Windows 10. That's a lot of users, Thats all MS want to see. When Steam wins, MS wins. No different to how MS want Mixer to have more users than Twitch. They want that eco-system.

https://www.statista.com/statistics/265033/proportion-of-operating-systems-used-on-the-online-gaming-platform-steam/

The reason MS supported the Xbox and 360 was because they needed to save Direct X, that console needed to be popular to drive forward DX to devs. Which it succeeded. Its why it was going to be called the Direct X Box. Thanks to games like Halo which single handed took on all of Nintendo and Sonys IPs and still managed to sell consoles and games to great success. Halo 3 was that good, even Sony trolled the Wiki as mentioned below.

https://n4g.com/news/65101/sony-insults-halo-3-on-wikipedia

In 2007 Sony insults Halo: On the Halo series page at Wikipedia, an edit originated from Sony Computer Entertainment casts aspersions on Microsoft’s Halo 3. In the Halo 3 section of the Halo page, Sony added “(Halo 3) wont look any better than Halo 2.” Since then, the Halo page has been corrected and locked from further vandalism. 

Currently Win10 store acts more like a X1 console than a Steam/Epic store which works fine for them. Its not competing with Steam directly anymore, or not at the same pace as the Epic Store is competing. MS are now just using the Win10 store to play console games on PC giving another incentive to own a Win10 OS over there competitors. Its decisions like these which is why MS make so much money quarterly. Corps want you in there eco-system and currently X1 doesn't need to be the only way to drive that strategy forward. Azure, Windows 10, Software Programs, Games and Social Apps like Mixer is the future of bringing the money to the MS bank, not how many Surface Pros, Nokia Phones or Xbox hardware sell.

There isn't many that are buying Switch at this moment for Zelda since it have over 2 years. So why not request Zelda BotW to launch on PS4 and X1 then?

Every argument you give to say it is reasonable to MS to release their games on Switch is about the same to justify MS games on X1, and with the benefit that they won't need to cut down due to power difference.

Again, it would come back to Nintendo being more dependent on their IPs than MS, and MS already moving towards being more platform-agnostic with the release of Xbone games on PC and games like Cuphead coming to Switch.

I cannot give Microsoft even that much credit, for as much money as they have, they have little curiosity to delve deeper as to what it means to live and die as a console maker. Microsoft has realized they cannot beat their competition anywhere, so they need to corner a market where the competition isnt as strong. Thats where google and multiplatform gaming is.

Still MS doesn't release in all platforms besides Minecraft that was already multi or cuphead that is a very small game. From that to Halo is a very big step, even if you portray it as not the latest Halo., and you put as if that would be the best decision for MS.