This was AFTER the Sony E3 announcements
No it wasn't.
The price cut was announced before E3, and this statement was made a day before the Sony press conference. MGS4 will almost definitely remain exclusive.
7/11/07:
* 9:00am - Nintendo Press Conference
* 9:00am-5:30pm - Meeting suites open at the Fairmont Hotel
* 11:30am - Sony Press Conference
* 1:00-6:30pm - Barker Hanger open to view games
* 2:00pm - Electronic Arts conference
* 3:15pm - Activision conference
* 4:30pm - Midway conference
* 5:45pm - Konami conference
Konami makes statement on 7/10/2007