Why not use KDE applications in Unity if you like the UI of Unity, but not the apps?
I really cannot see what you want coming from anybody. Email is all but dead. Mozilla’s Thunderbird gets little attention from its parent, so Evolution is not the only unloved child.
People collaborate differently now. Smartphones and tablets have taken over. People can collaborate face to face and in real time as opposed to posting a message and waiting. There is a social cost, loss of freedom and privacy, but people seem okay with being on call 24/7. (I am not in that camp, BTW)
The desktop computer is still around as are email clients and collaboration software, but they are a dying breed. So do not hold your breath hoping someone to back your idea. They are going where the trend is and I do not blame them.
There are some distributions that are stuck in the past, but their stock is falling. They have won over some diehards who won’t change, but are getting left behind. But do not count on them to help you either. They are happy with 1998-ish Evolution.
I do not use Ubuntu. I prefer KDE so am using Kubuntu. I like the UI. It can be tailored to work the way that I do. I love the applications. Dolphin is 100 times better than Nautilus as is K3b over Brasero. I could go on, but will spare you.
I agree that GNOME is making a mistake, but not in the way that you do. I think that they are not going far enough.