They are ridiculous because :Why are they ridiculous? I mean the way the second hand market keeps them so high is, but that's not on Nintendo. Older games ported on to it are set at the price the publisher thinks they'll get, which is why I tend not to buy them myself until they drop.
Their store, like any other, always has sales on too.
For multi-plats, the switch is normally the worst version. No one with a switch and another console has an incentive to get the switch version, being worse and more expensive.
For exclusives, 3+ years old games are often near full price.