The toshiba portege g900 has a ppi of 310, yet it was released 3 years ago. I remember some android phone released earlier than the iphone 4 with a similar high ppi. Many people don't like high dpi due to the pixels being too small and using software designed for 72-100dpi.

Metallic laptops tend to have wireless reception issues, conduct heat a bit too well onto consumer laps, have warping issues and can add weight. All of these problems have been present in macbook pros.