Okay, after spending 10 minutes trying to read that OP:
Of course there will be a PS4! The PS3's already sold 21 million units, over double the DreamCast's sales. SCE made a profit last quarter, albeit a very tiny one. Yes, the PS3 has lost money, but the PS2 and PS1 were both generation winners with over 100 million sales! The PSP should easily get 60-65 million sales before it dies out. Sony have some 30 first party IPs and 15 first party developers, as well as many second parties.
I swear, we get one of these threads every week.