1) There is no way Microsoft will release an OS that will only run on 5% of hardware
2) Many current laptops ARE ready for Vista, at least with the current "scare tactic" hardware requirements from MS
3) Their claim of a requirment for DX9 hardware support is bogus IMHO, it is based on last years technology; if they want to release a new OS next year they'll need something more flexible, and nothing is more flexible than some updated drivers.
Really, their aero interface is nothing special, I've been running XP MCE on a laptop with basic video for ages and it runs just fine, this is a Windows OS, it isn't quantum physics calculations. It will be in MS's best interest that their product runs on as many machines as possible without telling people they will get reduced capabilities. "Reduced" is a term that will put people off buying it, and they just know people won't be going out to all get a new PC just for Vista...