Earlier quoted context omitted.
But you have to subtract the operating costs, and still make your money back quickly before you have to pay to upgrade the hardware again.
In 3 years time, they'll still be selling these machines. A lot of companies still offer the Xeon's 3220, which, if I'm reading wiki correctly, first shipped in Jan 2007.
I have been using them for 8 years, they upgrade the hardware every 6-12 months to the most recent spec