Why many drivers in vista should be installed manually( by addressing Driver Store in system 32)?Although many of them are installed automatically in XP?

Vista is much more capable in identifying drivers than XP was, and even will go out on the web to locate them if you let it. The built in driver store is also much larger than it was in XP, making more drivers available.

But, it's impossible to include every driver in the distribution package. There's just too many of them, and not all of them are known to Microsoft.