They’re saving Mario Kart 9 for Switch 2.

And personally, I’d like to see them dig deeper into the Mario lure for characters instead doing some Orange Silver version of this character or bringing in more non-Mario characters (at that point it might as well be Nintendo Kart).

For example, why can’t we get Professor E.Gadd from Luigi’s Mansion as a playable racer? Or some of the RPG characters from Paper Mario, Mario and Luigi, or Super Mario RPG? Like Count Bleck, Dreambert, or Geno?

How about Pauline? Or a Pianta from Sunshine? Or a Luma from Galaxy?

Really make it MARIO Kart.

Also, the leap from NES to SNES was not "small" by any stretch of the imagination, it was huge, nothing on NES looks remotely in the same league as the likes of Donkey Kong Country or Yoshi's Island.

Oh no, please not more content into MK8. 48 tracks are more than enough - you already have to wait hours until your favourite track will be chosen in online mode. And the roaster and customizable parts are big enough. MK8 had its DLC on WiiU, which is already part of the Switch version. We need a completely new Mario Kart (maybe day/night system for every track?).

This could very well be one of the games Nintendo uses to push the "Switch Pro." Although, I'm not even sure if that's still a thing lol.

As much as I love Mario Kart, I think it severely lacks in features. Cups, Time Trials and Battle Mode. That's been it, for the majority of the games. They could add an adventure mode, boss fights, and all these amazing DKR/Crash Team Racing ideas, without having to add characters from different universes and turning it into Smash Bros Racing Edition. There is so much room for Mario Kart to grow on the Switch, just step outside the box for a bit. 

From Nintendo's POV there's just no reason to make MK9 for Switch when it would serve them much better as a system seller for Switch 2.

1 and 2. I'm sure Nintendo would have released 9 on Switch it 8 deluxe had sold normally for a port, but that's not the case. The game still sells like crazy, why waste a game on a system that cuts the legs off of another? Not to mention having MK9 for Switch 2 launch will help that console sell like crazy, so why cut the legs off that console as well before it even stands?

3. Well sure, if they were going to release 9 I hope they follow your idea here and re release it in better form on Switch 2. The problem with this is many won't like the precedent they are following. We already hear an endless line of complaints from people annoyed by them porting Wii U games to Switch, so if they continue that trend of making Switch games port to Switch 2 those same triggered people will continue in their ways. Not really a problem for Nintendo as they will sell more games that way. If, however, 9 is exclusive to Switch and 10 doesn't come out many years into Switch 2's life because of that, then this is not a good idea.

Also, that 10 year gap would be for just this gen. These Wii U re-releases are happening because Wii U bombed and Nintendo is trying to salvage as much profit from good games that didn't sell to their potential in the previous system. Switch is a success, and so are it's games, so we won't have that problem with Switch 2 and should enjoy a healthy amount of original exclusives rather than Deluxe ports. I expect MK9 on their next device, MK10 on the one after that, and so on (unless they have a device bomb and then they may do the deluxe MK treatment again).

Lastly, there are a number of unexplored ips this gen that have done well before, some even recently, that they haven't tapped yet. Kid Icarus, Mother/Earthbound, Advanced Wars, Mario and Luigi, etc. I would rather they focus on making their lineup varied, appealing to a wide range of gamers, than just focus on sequels to already successful Switch games, but that's just my opinion.

Mario Kart 8 DX is such a huge title. People that are worried about its legs being cut by MK9 can rest easy. Most of the switch owners will be purchasing both games, I can assure you.

I don't understand this perspective. If you have bought 8D, and 9 comes out on the same system, you are far less likely to buy it than you would be if it came out on a new system. It's not like these are games with new stories people want to explore. Millions of sales for both game will poof, be gone, because you released two games on the same system.

If you don't own MK on Switch yet, and 9 is out, you now won't buy 8D, whereas maybe you would have bought 8D on Switch AND 9 on Switch 2.

Nintendo will do whatever leads to the most sales and least cannibalism of sales overall.

Now, releasing a new Diddy Kong Racing Game, or F-Zero, will lead to no cannibalism of MK, more thirst for MK9 and Switch 2, and success for other ips all the while appealing to fans of those series that felt neglected.

It's obvious why you can't see it. You are only putting this from your own perspective or the gamer that frequently visits gaming forums perspective, that represents a really tiny group.

Most of people don't wanna buy a new hardware to get a sequel of the game that they enjoyed playing on the system that they currently own. 

I know what I am saying bc I worked at a game shop during the MK8 release on 2014 and I was frequently asked if there's a wii version for MK8 after I explained that wii u games can't run on a wii system.

It's cool and all having other racing games from forgotten IPs, but Mario Kart is the brand that gets the attention. Having 2 MK on the same system would be mind blowing for many. Too hard to miss.