I'm gonna guess this is the beefed-up "slim," akin to the $399 2TB SlimBone. If it does turn out to be a $399 Neo, then it will almost certainly destroy the sales of the aforementioned $399 2TB SlimBone, and likely sales of the $299 SlimBone and $299 PS4 as well; a $399 PS4.5 is kind of a no-brainer, especially if you were already considering the $349 PS4 they were just selling a second ago.
Then again, if people are right about PS4.5 being doomed to forced obsolescence in a couple of years by PS5, then it might be better to just wait for that.
Then again, if Sony are being truthful about more frequent hardware refreshes and in a couple of years you'll be able to get a far more powerful PS5.5 for practically the same price as the PS5, then it might be better to just wait for that.
Then again, if the PS5.5 is doomed to forced obsolescence in a few years because PS6