"Steam" doesn't decide to have discounted sales -- games are heavily discounted because developers compete against one another for attention. Nintendo and Sony generally have less need to do this.

> Nintendo and Sony generally have less need to do this.

The prime Nintendo games (i.e. Animal Crossing, Pokemon and anything Mario related) are rarely discounted, yes - and Nintendo can do this because these games have borderline drooling fanbases and the games aren't available anywhere else.

But everything else? There's constantly something on sale on the Switch store.

Does that distinction matter? Seems like a simple case of open platform -> more competition -> lower prices.

It does not :)