You are quite correct, Downix. With today's technology, who knows how much of it was bought off the shelf from another company or companies or custom made by another company.
Kiario,
Yes. It is possible to covert it to single player, but it's not worth the effort. The cost alone would kill any such effort. Codewalker is correct that NCSoft doesn't have the talent to convert it in house anymore. They're not going to develop that talent either. And without the talent, they can't.
To do the conversion, you would need the server engine with all of its dependencies (login server, database server, gaming engine, underlying OS or a compatible OS). All of those alone could cost thousands. The hardware to run it on which could be very specific and prohibitively expensive. The database itself could have been Oracle running on a Solaris frame for example. All of that would have to be converted to run on Windows. You would also have to patch the client to look for its server on the loopback network interface.
You must understand that the client is little more than a dumb terminal. Sure it has the graphics, sounds, music, textures, etc. to give you the immersive feeling. But it has no gaming engine. It cannot play anything. It literally displays what the server tells it to display. Plays the sounds it is told to play. The client's functions are get input from you and display the effects of that input.
It really is as simple as: You hit the up arrow to step forward. Client sends step forward command to server. Server updates record of your toon showing it moved forward. Server tells client to update the graphics and play the sound of the step. You see the floor, walls, ceiling move. Some textures become more clear. You hear a thud of a foot step. That's the limits of the client.
The server is the one that decides you just went into range of a hellion, and he's going to attack you. The server (playing the role of the hellion) executes the attack, updates your toon's record, and send the additional messages to your client saying, display hellion, remove 5% health from your toon, flash the screen with red so you (the player) see that you've been hit. All those decisions were done on the server.
MMOs are classic 2 and 3 Tier client/server applications. Each part is useless without the other part(s).
LV