Whether the iMac Pro is bought by the people who actually make movies, or just the people who want to think they make movies and must have the newest machine going, remains to be seen. It is certainly a very powerful computer, but like a consumer-grade machine it is not upgradable. Apple said it would deliver the iMac Pro in December, and it has by a whisker.
The iMac Pro is configurable not upgradeable – The new Mac Pro coming next year will be the upgradeable Mac – it always has been. Customers who wish to regularly upgrade their components over time would suit Mac Pro customers. This new iMac Pro is the most powerful Mac you can get right now and suits professional video/audio and gamers who will enjoy the processing power.