I'm saddened to see this but it makes a lot of sense. At this point, Blackmagic probably doesn't want to market with 2 year old iMac's and dongles attached to a MacBook Pro. Most of their old product pictures featured Apple Thunderbolt Displays, and since Apple decided to exit the display business, they had to find other things to use. IMO, Apple had the market cornered on most appealing displays. The black/aluminum look really married to things Blackmagic was putting out.
In those terms, I think Blackmagic had a similar industrial design, even mimicked elements of their web design for a while. BM is a good company and is committed to how things look to customers. Even their packaging is great. Apple simply stopped making anything for them to market with.
The oldest iMac was released in October of 2015. It's 16 months old which is not quite two years old yet. That said Apple better have something up their sleeves.
It's only downhill from here if Tim and company continue to ignore the signs and run Steve's legacy into the ground.