According to this Kotaku piece, KBC Securities Japan analyst Hiroshi Kamide reckons that DS's day has dawned, both in Japan and abroad.
"Casual gaming growth has been driven over the last three years by the Nintendo DS platform," he said. "Demand has peaked in Japan, and we believe is currently peaking overseas. Compounded by a less robust retail environment, we expect to see a decline in the handheld sector."
Kamide added: "The casual market looks more exposed to an economic downturn, due to its non-essential nature. The sector remains 'hit-driven', which provides a positive outlook for the companies with strong core title line-ups."
DS was shown yesterday to be the biggest selling machine in Japan last year, having moved 6.34 million units.