In 20$ a die, they could sell Gameboy style cartridges for different models.

That would be very cool, get an upgraded model every couple of months. Maybe PCIe form factor.

Yes, and even holding couple of cartridges for different scenarios e.g image generation, coding, tts/stt, etc

dude that would be so incredibly cool

Make them shaped like floppy disks to confuse the younger generations.