It's really hard to compare a dedicated machine with a general purpose one (PCs, like the homebrew PS4). A regular computer with specs comparable to PS360 wouldn't deliver the same graphical results. Videogame SDKs give a very low level access to the hardware and they are projected with some really bleeding edge tech (like X360 memory architeture or PS3 processor/memory combo).
Simply think about this: listening to MP3 songs (128 kbps). You will need, at least, an Intel 486 (66MHz). A MP3 player (dedicated device) with a 16 bit CPU running at 16 MHz can do the same job using a single battery for 10 hours.
Besides that, I really doubt that a PS4 would bring this very little visual upgrade. People simply wouldn't expend their money in a new console for just that. Next gen will only begin for Sony/MS if they can really do a reasonable jump in processing power (not just real 1080p or 60fps, it's just not enough to appeal to the mass market).








