On my personally opinion, I think it is because Nintendo players are used to play on systems which were outperformed by other same gen consoles since a decade ago, even though the graphics on their systems are mostly left behind by one gen, like 3DS performed like PSP, or Switch performed like PS3/360, they can still feel the upgrade on graphic side, comparing with last gen Nintendo consoles instead of other same gen consoles. just make myself an example, I played every single PM games from GameBoy to Swtich era, every time GF made upgrade on graphics for new gen console, I did feel impressed, because I compared it to the last gen graphics. I think that makes sense why people feel impressed by switch running some games no matter current gen or last gen.
Being used to systems with less power can be a factor, but for me at least it has more to do with the fact that when I was a kid mobile graphics looked like this:
So seeing something like Doom 2016 or Hellblade running on a handheld just really impresses on me how incredibly far we've come just in my lifetime.
Exactly, that's what I'm talking about, and one more thing, Nintendo and its games are just barely attractive because of graphics, can't say there's no good looking games on Nintendo systems, it's just unlike Sony, they focus way more on gameplay than graphic stuff.