The idea of catering to audience differences is probably a factor in the success: let's be real the PS4 Xbox1 and PC cater to a lot of the same stuff, and people who aren't getting what they want elsewhere are probably jumping for the Switch.

I'm reminded of a few Jim Sterling comments about starving markets. Games like Mario O, Octopath, Mario Rabbids, and the like do a lot for people not happy with shooters and sports. Heck, imagine the interest that a new big Horror title might do on the Switch, for example.

It's also possible that Nintendo is getting a boost from the issues on Steam: taking over as the top Indie platform.

Though I'll fully admit I am not the biggest Indie expert, and I'd probably chop it up to rarer game types if I was the head of Nintendo

3d World is still better than Odyssey. 

3D world wasn't even a proper 3D Mario. Odyssey was a return to form from the Galaxy days. 

No idea what a proper 3D Mario game is, but regardless Mario 3D World was absolutely amazing. Best couch coop game ever crafted.

Ironic considering that Galaxy was the 3D game that first revitilized the course formula and that Galaxy and the 3D series are actually much closer to each other than Galaxy and Odyssey. 

Hard to be a "return to form" from Galaxy when not even Nintendo acknowledges that as an accurate comparison. 

will repeat myself again 3d world is by far my favorite 3d Mario all others I played once and never touched again 3d world I played for hundreds of hours

lol can't tell that to my kids they insist that 3d world is "real" Mario  after playing Odyssey

While there were a fair amount of one off Galaxies with a single star, the vast majority of the gameplay in SMG was spent exploring the same open ended Galaxies multiple times to get every star. The course formula on the other hand returns the games to the overworld layout from SMB3, and SM World. There's a World, a map, and multiple levels to go to. All levels are one-off linear events. That is the course formula. Galaxy just barely touches it, while 3D world dives right into it, bathes in it, and guzzles it down. As far as Mario Games go 3D World couldn't be more different from 64, Sunshine, Galaxy, and Odyssey. 

All four games have many huge explorable levels with multiple Stars/Shinies/Whateverwewanttocallthem. All four games have the camera follow Mario from behind the back or in some other non-isometric fashion, for the majority of the game. All four games have big dynamic bosses that don't boil down to just jumping on repeatedly to defeat. 

So where have you heard Nintendo denying the similarities between Galaxy and Odyssey? If Nintendo said that the cape from SMW and the Tanooki Suit from SMB3 were not essentially the same power up would you believe that too? 

That's because they are too young to know any better. 3D World was probably their first Mario game. Either that or you mostly raised them on 2D stuff like SMB3, World, NSMB, NSMBU, etc. 

The software is good.

It's that simple.

Don't get me wrong, Odyssey was good, but Mario 3D World is just better. I found 3D World more creative and just plain old more fun. If I were to rank Mario 3D games:

1) Galaxy 1/2
2) 3D World
3) Mario 64
4) Odyssey
5) Sunshine

The problem with Odyssey is many of the moons feel lazy, as opposed to intentional.  Half the moons are just sitting around in plain sight with little thought to placement within the level.  Odyssey has a ton of outfits for Mario, but they don't have any gameplay implications, so the outfits feel arbitrary and serve only as a means to make the game appear deeper/longer than it is.  Again, I like Odyssey, a solid 8/10 (maybe 9/10).  But for me Galaxy and 3D World are the best 3D Mario games.