Well, for sure products like Share Point on premise will still be on the market. At Ignite it was emphasized that Microsoft is coming out with new Server products because it's believes in a "Hybrid IT" world.
I remember an article I wrote for Windows IT Pro Magazine called "Do you Drive a Hybrid" http://windowsitpro.com/windows-client/do-you-drive-hybrid
I can't believe that was back in October 2008. I wrote it in the airport, coming back from one of our Minasi meetings in Virginia Beach. Now look where we are. I did not imagine how much investment would be put into the datacenters that created the Marketing phrase that we are stuck with called "The Cloud" Perhaps it's the reason why I like terms that are now more accurate, like OL and OnPrem.
All that being said, SharePoint OL is already highly integrated within Dynamics 365. The official release will be in November. But there is a ton of "OL Print" on it already. SharePoint will become more of a business tool. By saying that, I do not mean that developers will be creating business tools for it as a platform, although I have seen that be quite successful. I see it as a dev platform and business process platform. Since Dynamics 365 is a business application suite, and Microsoft is positioning Share Point to be an engine in Business processes, I would expect to see strong integration grow. Indeed, there already exist strong connections between these components in O365.
So because businesses will be the customers of the service, it only makes sense to view the "Business case" for Share Point, and gain the present and future tools as part of an IT Pro's skill set so we can be the ones to make that happen.
With the use of Azure SQL storage, Microsoft can use that in the background to enhance the capacity of Share Point OL. The features in SQL 2016 for controlling "Hot" and "Cold" data give some insight on how Share Point data that is "Active Income Generating" can be segregated from "Inert Archive Data" that can slow business process down. Not that "Cold" data does not have value. There is a difference though between a good nugget found on the ground and ten tons of "Pay Dirt" that has to be put through a wash plant to find two ounces of gold dust". Yes, I watch "Gold Rush" for a while now.
As for uploading large files into SharePoint OL, it may well a hybrid situation may be an option.
A more Dynamic approach will have to be used in order to know when data is hot and useful and when it is not. Reporting will be key.
It will require using tools in several applications to keep decision makers informed on many levels to stay "Found" regarding their business processes. For years now we have been admonished by IT professionals that we needed to become integrated into our firms business. Frankly, I could never see how IT professionals and Developers were not part of it. Perhaps it was from an erroneous mind set on the part of IT pros themselves or the perception make by business professionals that were not interested in the details. Well, those days are gone.
Also gone are the "We solve all our problems with one application and platform" ways of thinking. So keep SharePoint as part of the "Problem Solving" and "Tool Making" machine. Tie it to other apps and learn how to mine data that is stored there with an aim to revenue generation.
For sure, this is just IMHO. But look where we are now!!!