Different IM clients seem to have very high concentrations in certain populations, many have reached critical mass where it's a very long and near impossible process to change. AOL has reached that state in many places in America and MSNM seems to be in that state where I live.
That's true. Where I live in Canada, AIM is practically unheard of, while MSN is used by everyone. At the same time, I've been a member before on a forum with a predominently American userbase, and everyone talked on AIM, while virtually no one had any MSN contact informtation. That's going to be a large problem for Google, not to mention it will already suffer from the fact that you still need an invite to get a Gmail account. I mean, with MSN anyone can get a free hotmail account, no problem, and you don't even need a hotmail account, you can get your current email address to work with MSN, same with AIM. You need Gmail to use Google talk, and that's going to set things back a bit.
Not to mention the aggrevation of adding your contacts over again, when you can already easily talk to them with your current IM client. Oh well, like I said before, I like Google, so good luck to them.