If it's literally a full remake with the Odyssey engine, yes, especially if they are all bundled for $60. If it's just the same visuals with some HD textures here and there or a resolution bump, no.

And if they do the HD Odyssey engine route and ADD some feature (s) like online leaderboards or online multiplayer or newpnew bosses, people will go nuts.

I don't see any of those titles selling nowhere as much as big AAA Switch games, the ones that are pulling ~20million plus

Switch current catalog is what is selling the console, not those games. Nobody buys a console to play remastered versions of old games

Assuming these games DO exist and DO come out by the end of the year...

We don't have that many Nintendo compilations to compare a Mario Collection with. That said, Kirby's Dream Collection on the Wii sold 0.69 million copies, about 40% as well as the previous year's Kirby title, Return to Dream Land, while Metroid Prime Trilogy sold 43% as well as Metroid Prime 3 did a few years earlier. So I think it's perfectly reasonable to expect a 3D Mario Collection to sell somewhere in the 30% to 50% of Odyssey range over its lifetime. That would equal 5 to 9 million copies lifetime, not exactly a bad total.

As for 3D World Deluxe, the best comparison would be with other Wii U titles on Switch. Some games like Mario Kart 8 sold way better on Switch than the Wii U, and even smaller games like New Super Mario Bros U, Donkey Kong Country: Tropical Freeze, Pokken, etc. Only the rare oddball like Captain Toad and Hyrule Warriors doesn't exceed Wii U sales, and even those were in part due to competition from the 3DS versions. So it's generally reasonable to expect 3D World Deluxe to sell in line with what it sold on the Wii U, 5 to 6 million copies.

Combined, that would be 10 to 15 million copies between the compilation and the port, assuming of course that the release of two 3D Mario titles doesn't cannibalize sales. Regardless, that WOULD be enough to push sales, but NOT on par with the big hits of 2017, 2018, and 2019.

Mario Kart 8 Deluxe? Not to mention how the best-selling games on the X1 and PS4 are Grand Theft Auto V.

Or heck, Super Mario All-Stars? It's not exactly like Nintendo already doesn't have form in this area, even if that did have an added sweetener in the form of The Lost Levels.

Not as big as previous years, but big enough. We'll be frustrated that they are the big holiday titles. But the more casual player/consumer will likely eat them up with no complaints.
If these are real, I honestly think we'll get three releases. Super Mario 64/Super Mario Sunshine HD Collection, Super Mario Galaxy HD Collection, and Super Mario 3D World Deluxe. And Nintendo will charge $60 for all of them. There's virtually no way Nintendo would put more than 2 remastered 3D Mario games in one package for $60 or less.

Hardly old games in the strict meaning of the word. We are talking about a Nintendo 64 and Nintendo Game Cube games. Unless they really remake the game and not only re-release with fewer better assets/resolution I have no reason to believe they will pull out huge numbers 

I mean, it'll be big but I won't bite. I can't get myself excited about games I've already played for countless hours as a holiday title. If this truly is 3+ 3D Mario games in 1, then that's some great value for Nintendo but like I said as someone who has these games burned into their memory, it's probably not going to do much for me. Plus, I didn't really love 3D World as much as others. I think 3D Land is the better platformer. FIGHT ME...please don't though.

Edit: Now, if these were remakes and not remasters like the orignal Mario All Stars, I'd be all over this. 

Remember Pikmin 4? It was close to completion in 2014.

Tell that to GTA V and Sony gamers