I dont think it will beat the PS2 but I think the Playstation brand can regain some of its old market share with the PS4

I have no idea whether the next Playstation will outsell the PS2.

I do however believe that Sony is in the best position of the 3 Console makers. Though that is based on the rumors we have all heard that have yet to be confirmed. But if the Console does launch at $399.99, is as powerful as the "leaked" specs appear to be, and has the 1st party games at launch (and within the first 12 months) that it seems it will have I can see it being a big success.

I certainly don't think the PS3 was a failure. Sony wanted to push Blu Ray and win that format war... and it did. But no doubt the PS3 had a rough couple years in the beginning. And that's saying it nicely. The high price, weak exclusive launch titles, and coming out a full year after the 360 really hurt the PS3. It looks like they addressed those issues with the next Playstation, if the rumors are true anyway. Also it looks like development for the PS4 will be easier for developers which certainly helps