I feel Sony is going to support the PS3 for a few more years and putting their new slim model at a much lower price right now will give them nowhere to go in the future. This new model should give them a bump in sales for October and early November. I'm guessing Sony will have very competitive deals for Black Friday, ending November on a high note. After the November and December high X-Mas sales die down they will be able to have a price cut next year, possibly at E3 after the announcement of the PS4.

To people saying 'the people who want a PS3 have already bought one' must have forgot that the PS2 has sold around 153 million units worldwide to date while the PS3 and Xbox 360 are at around 67 million units sold to date.
What this means to me is there are plenty of people around the world who will continue to support the older console like they have done with the PS2 after the new console has come out. This slimmer, cheaper to make model, gives Sony the opportunity to lower the price over the next few years.
The PS2 has sold around 54.2 million units since the PS3 launch in 2006. The PS3 is a long way from being dead even if people like me have moved on to the PS4.