Microsoft Confirms Xbox 360 Arcade has 256 MB of Internal Storage

Microsoft has officially confirmed the new Xbox 360 Arcade will have its own 256 MB of internal storage. A Microsoft spokesperson said:

"We are constantly updating the console’s more than 1700 internal components. We can confirm that we are moving to internal memory for the Xbox 360 Arcade. The physical internal memory is the same size as the previous external memory units - 256MB."

Why couldn’t Microsoft have done this in the first place, instead of forcing previous customers to buy a memory card?