Obsolete Timing Belts on Brother embroidery machine 780D?

Why does Brother sell an embroidery machine and has one of the belt to become OBSOLETE ? I have a Brother Embroidery machine PE-780D and need to replace motor and timing belts.I can find the motor and two of the timing belts, but Brother said their timing belt #XA2123051 was obsolete.Is this a way to run a GOOD sewing machine co.? Can anyone help me find a replacement. Thanks, Dean 2/11/14