I don't think it'd be particularly sad. I mean, sure, you won't get any more music from that particular collaboration, but I'm sure most if not all of the members would either solo or make another band. They're true musicians. If they didn't want to work together anymore but still did because they felt obligated to fans, their creations wouldn't be that great anymore either. If they felt the need to free themselves from each other, so be it. At least you'd still have the older stuff, right?