As for clearing it in an hour, clearing each of the levels once isn't a challenge, nor is it the point of the game. If you want to complete the whole thing you must play each of the levels 4 times, and that's assuming you play perfectly each time (and you won't). And that's just for Tour mode. For Toad Rally mode you're competing against other people (not live, but against their time trial ghosts) and doing tricks to try and impress toads, where winning gives you a bunch of coins and a bunch of toads. And then you use those toads in the kingdom builder mode to unlock new items to put in your kingdom and to upgrade your castle, etc.
So yeah, you can play through all of the levels once pretty quickly if you want. But that's not really experiencing the game.
Short play sessions have nothing to do with depth or lack of it.
You are right that there are many ways to play Mario on many different devices, and I'm not arguing that focused gameplay in front of a big tv isn't the best way to play for extended hours, but for ten minutes waiting in a queue or on the subway (when there is an internet connection available - don't get me started on that because I'm not a big enough fanboi to be happy with that situation), it's much more convenient than carrying along a 3DS. I think Nintendo did their homework on how people will play this game. It's accessible enough to play in short bursts, which suits mobile gamers.
I do respect that you don't see any depth in this. That's fine. I know that enjoyment of games is very subjective. I'm biased in that I grew up in the golden era of 8 and 16-bit 2D games, so I'm aware that this type of game has more appeal to me than others. (Nintendo probably knows that my demographic is more likely to convert to a purchase as well, but I digress) I've tried to stay engaged with recent stuff on Playstation, but triple A titles require large time commitments and have lots of grind, and hence don't appeal to me. This does.
I'm curious to find out how conversion from Pokemon Go -> Pokemon Sun/Moon games and Mario Run -> Mario Switch plays out, because both mobile games have succeeded at getting me more interested in investing time and money into their big-brother console relatives.
Huh. That's how I feel about Megaman. I suppose you disagree?
Anyways, since you're talking about new games, and seem to have an enjoyment of the 8-bits, have you tried Shovel Knight? It's incredibly well designed, and absolutely packed with content (with a third campaign coming next year. for free).
You say you spent $10 on a game that you beat in an hour. I get that there's replayability but there's only so much in a game like that.
If I really wanted to play Mario I could go home and play it on dozens of different devices on a nice TV while resting comfortably instead of on a limited form factor in public where there's dozens of other things to do.
Much respect to Nintendo for making a good game, but it seems like a game that just exists because it can. No depth. What value do we get as consumers if we encourage the game industry to move further in this direction?