While I realize Adam has clarified this to a certain degree, this whole response has just been clownshoes and this is just yet another example of it. Clearly they're not in the right frame of mind if one of their top of mind concerns is the effect of the cost of sms messaging for authetication on their bottom line.
Last time I checked the problem was on their end, not on their users'. Although adding a second factor is undiably a good thing, it's not going to do much for security on their end.
In addition to that, I suspect a large number of bitcoin/mtgox users own a smartphone. There's a HOTP implementation for pretty much all platforms - completely free..