I honestly don't think that they didn't know that Brothers In Arms would become such a hit. I think they knew it really well. The songs are unbelievably strong, all riffs are catchy, almost no weak links in the whole album, recorded in the state-of-the-art fashion, in one of the best studios in the world, in the new domain and format, with cutting edge technology. So it was doomed to be successful in a way.
Once I looked up the 1986 Grammy award and realized that "No Jacket Required" won the album of the year back then. I mean, I respect Phil Collins and all, but this album is nowhere near Brothers In Arms, this was simply ridiculous and showed how pointless all these awards are.