But $20-40 for each game.

A $40 game provides 20-100 hours of high quality gameplay, which I think is a good value.

Playdate is not in the same market as the 2DS, or really anywhere near it. It's not trying to compete on any of the games-industry metrics, nor could it.

It's like comparing the latest Avengers movie with a niche YouTube show. You can compare the price of a movie ticket with a Patreon subscription, but what are you even comparing?

No, it doesn't. It only might. You or your kids might play it for 10 minutes and never touch it again.

How many people on HN have $100s spent on Steam games they haven't even installed once and probably never will? Or games they finally played but didn't like, yet too much time elapsed for a refund?

You could make the same argument about anything. No product is worth the money it costs if you never put it to use.