Erm, no-one has answered my question, so I'll add a few thoughts of my own.
I think we're all agreed that we want From to keep on developing great games like Demon Souls and Dark Souls, right? O.K. then, I'll state the obvious which is that game development costs money, a lot of money, so it makes perfect sense to me that From will want their games to have as big a user base as possible in order to shift more copies of the game in order to fund their dev studio. GfWL may not suit those people who have a lot of computer gaming experience and in depth knowledge (why this is I still don't know) but the game will reach a wider audience if it's on GfWL and the result is that From make more money.
I think we're all agreed that we want From to keep on developing great games like Demon Souls and Dark Souls, right? O.K. then, I'll state the obvious which is that game development costs money, a lot of money, so it makes perfect sense to me that From will want their games to have as big a user base as possible in order to shift more copies of the game in order to fund their dev studio. GfWL may not suit those people who have a lot of computer gaming experience and in depth knowledge (why this is I still don't know) but the game will reach a wider audience if it's on GfWL and the result is that From make more money.