The biggest reason is plain and simple: laptops are one of the easiest business expenses to write off. Everyone that can write off business expenses, from high end executives to small business owners, choose a higher end laptop, because, if you do the math, business owners get between 30-40% off their business purchases. It’s not quite a coupon they hand you when you open your own business, but rather it comes out of your total taxable income. Thus, that’s less income that is taxed, so instead of losing 30-40% on the amount of money it costs for a laptop, they put the money toward a “better” cause. The reality of the situation is that most businessmen only use the Microsoft Office suite (PowerPoint, Outlook, Excel, Word, etc) and the internet/email. These tasks could (though it may not be as much fun) be done with an integrated graphics card, and 512 MB of RAM. Maybe if you’re doing lots of integrated movies and pictures in PowerPoint presentations, it could require 1-2 Gigabytes.
So, the moral of the story is, if you’re thinking of buying a laptop and can write it off, it may be a wise decision to get a laptop with all the bells and whistles. On the other hand, if you’re just starting a business, or are an entry level business person, don’t go investing a couple thousand dollars in a laptop just because it called a “business” laptop. Usually, you don’t need even half of the overpriced upgrades that laptop companies charge you for in business laptop models.