This is just... No
1. The 360 is no more of a personal computer than the PS3 is. If anything, the reverse is more true (or was) since the PS3 has (had) the option to install an actual desktop operating system on it. You could do web browsing, document editing/creation, video playback, music playback, picture editing/creation/viewing, and pretty much anything else you can imagine (with varying degrees of usability) on a PS3. The Xbox 360 can't even browse the web, let alone install a desktop OS.
2. The 360 and your standard PC have almost nothing in common architecture-wise. Your 360 is PPC-based, whereas your desktop is Intel-based (exceptions for people with old Mac PCs). The thing that allows PC-360 porting easily is that the 360 uses a slightly-modified version of DX 9, which has nothing to do with architecture at all. Almost all the other dependencies and APIs that a gaming programmer would rely on are non-existant on the 360, which is why both the 360 and PS3 use SDKs for development to ease the process.
3. The PS3 is not a streaming machine. Yes, it can stream, but when playing a game you are not simply streaming the content off the disc, there is so much more and countless calls made to the PS3 OS and various APIs
4. Since no console has ever really shared much in common with the PC, and gaming on consoles has been around for many years, I say the statement that most developers are coming from the PC or started there is complete nonsense. There are many console-only developers in the "western world"
5. Don't even know what that utter nonsense about thinking like a streaming machine when programming for supercomputers is all about.
Edit: meant PC in #4, not PS3
Ok, I wasn't talking in detail. It was a very abstract view on things, because I didn't know how detailed I can go so that I'm understood.
I guess we're meaning the same thing, but let me explain
1) A PC isn't defined by a web browser or a PC OS, but I know what you want to tell me and I can ensure you I know that, I said the 360 is similar to the PC because of...see point 2)
2) Ok, you're right on a detailed level, but I'm on an abstract programers view of things. I am at API level view, and there a PC and a XBOX360 is very similar while the PS3 is different.
3) The PS3 is more a streaming machine than the other machines. See point 5) for my explanation.
4) Well, here I don't agree with you. Every console programer started at PC. No one learned programing at the console. Every console programer at least once programed DX.
Every programer started with a lot of RAM in their PCs nowadays.
5) As you may know so called Vector Processors were used for super computers a lot and is still used for them, even if it is not that common anymore, thats why I compared those.
The PS3 CPU consists of one PPC processor and seven (actually only six, the seventh is used for redundency) so called SEP (Synergistic Processing Elements). Those things include the Vector Processors. The whole design of the PS3 with its 256 shared memory@3.4GHz and 256MB@700MHz VRAM and a Blue Ray support (high data rate compared to DVD) is designed for a lot of streaming, thats why I said streaming machine. Only few memory, but very fast processing speed and data rate, thats the definition of a streaming machine I would say (there is no official definition). Of course 256MB is very much and therefor I bent this definition, but as I said, I didn't want to go into too much detail. I just want to give a very astract point of view.
So, I guess the misunderstanding occured because I was talking about a very abstract view on this machines while you went into details.
But its good that you pointed that out, its always good to see both the detailed and abstract view.
ad 4) Its more difficult to program on few RAM and a lot of speed than vice versa, I took this from my own experience, maybe I'm wrong though.