Mainstream laptops usually cost ~500-800$ so it will take awhile before SSDs are cheap enough to be put in those (assuming there is no dramatic change in the price of other components). At 1$/GB, SSDs may be cheap enough to be standard in premium computers (possibly Macs), but I can't see a 500$ SSD in 700$ computer, makes no sense at all.
I can completely see a $250 256GB SSD in a typical $1,000-$1,200 corporate issue notebook (such as the HP Elitebook) in a year or two. Traveling consultants, salespeople, and bankers aren't producing terabytes of data. I'd venture to guess that most of these people have less than 100GB used up out of the 250-320GB that these computers come with, and most of it by the OS and applications. The vast majority of these people can't tell you what kind of processor or GPU is in their computer, or how big the hard drive is, but will notice if a computer boots up or shuts down in 15 seconds instead of a minute.