Sorry, I didn't infer that you were looking for a commercial sales games platform. You are right about the 32blit, however I don't think you're right about the playdate. If the 32blit is a niche product (which I'll admit it definitely is) the playdate is being made as a niche within a niche product and the numbers that are made in total will be a limiting factor. While the HN crowd seem to be able to see this for what it is and mostly wouldn't think twice about splunking 150 on this, I'm not getting the same feeling from any other handheld/retro/modern gaming communities. a few collectors are going "well it looks nice and well designed..." they're also the type who will buy one just to sit it on a shelf with their other oddball gaming hardware. I doubt the playdate will be any more viable to base a game business on than the 32blit, however from a different set of reasons, but along the same lines as people who buy the Pocket Operators as neat gadgets, but have no intent to actually make music with past the first few days of novelty.
of course you could try the Pico-8 games on itch.io route which is a well travelled path and probably a much bigger target audience