Anyway bought this game used on the PS2... never got around to even popping it in. Then bought it for the Wii thinking this time I'd play it, and got an hour or so in before stopping. Tempted to buy it a third time XD I hear such good things that I really want to like it...

Since it's obviously inspired by Zelda, it's very unsurprising that it would do well on Nintendo consoles. Not every kind of game is necessarily worth porting to Switch, but with games like this that aren't pushing hardware and are similar to one of Nintendo's biggest franchises, it's a no brainer.

This also speaks to the value of putting in effort. Okami was highly praised but generally considered a flop. But with what was probably not much work in porting, they got an extra 2 million or so copies out of it. I'm not always in favor of remakes, but in some ways it's a good thing that making a quality game can pay dividends over many years.

That statement is true about a lot of games for a lot of people that generation =)

It was the generational boom from the adopters of 8 and 16-bit consoles who finally got money. Those numbers were a lot higher than the X number of 8 and 16-bit consoles that sold, because usually one NES had multiple users between friends and families; PS2 was probably the first console I can recall where most people used it solitary. ANYWAY, around this time games many games became very cheap, and that caused these gamers with a lot of excess money to buy more than they'd ever play.

It might be Dreamcast was the first... At least a similar situation occurred with piracy and bootlegged copies.

Thread Re-railed =)

I couldn't find numbers, but I think Stardew Valley is a candidate. Also a brilliant game. They report total sales, and those went up drastically 
https://www.eurogamer.net/articles/2018-01-19-nintendo-switchs-most-downloaded-game-in-2017-was-stardew-valley

While the times don't match up entirely, it seems that by early 2018, after a few months of release, the Switch version of Stardew Valley had already sold 1 million copies, and spent a great deal of time after that near the top of the charts. Across all platforms Stardew Valley has sold 10 million copies as of January 2020. Stardew Valley is also the top selling indie game on Switch as of 2019 with Hollow Knight in second: https://www.gamesindustry.biz/articles/2019-03-22-stardew-valley-is-the-best-selling-indie-game-on-nintendo-switch-to-date 

Dead Cells sold more on the Switch too iirc

And ps2?