Because it just isn't a 360 price-cut rumour party til the Wall Street Journal turns up. According to "people familiar with the matter", the 360 Pro's price will be cut by $50 "as early as Sunday", just in time for Microsoft's E3 keynote on Monday. As with the other 1,097 price-cut leaks, there's no word on whether the Arcade and Elite models will be slashed as well.
Microsoft to Cut Xbox 360 Pro Price [Wall Street Journal (sub required)]