Forum Discussion
A generic question about Office 365
Interesting question, I think you are on the right track. My understanding is most new features are born in the cloud and don't correlate with any on-premise equivalent. Exchange Online isn't just Exchange Server 2016 with a slightly different build. There is some crossover with features of course (and a shared codebase) but Office 365 is way ahead of what Microsoft ship to on-premise customers. Some Office 365 features might get shipped in the next on-premise version like Exchange Server 2016 but lots of features are increasingly only available in Office 365. One example I can think of is Focused Inbox, which only applies to Office 365 Exchange Online tenants and users. Microsoft touched on some of these topics with this article - https://blogs.technet.microsoft.com/wbaer/2017/05/16/sharepoint-server-2016-and-beyond/.
Short version...
In the beginning, there was Business Productivity Online Services, built with Exchange 2007. That product was designed for on-premises and was inflexible and poorly performing when exposed to cloud demands.
Next came the launch of Office 365 (June 2011), when the products were based on Exchange 2010, SharePoint 2010, and Lync 2010. These versions had more cloud engineering in them and the advent of PowerShell (in particular) helped Microsoft manage the cloud base.
Office 365 upgraded to the Exchange 2013, SharePoint 2013, etc.-based code in early 2014. These versions were the first to have been truly engineered for cloud platforms and included a great deal more automation (like Managed Availability).
Now Office 365 runs the Exchange 2016, SharePoint 2016, etc. code as its basic workloads. Today, not much engineering effort is expended (in percentage terms) on the on-premises products and the vast majority if not all innovation is found inside Office 365.
What's equally important is the way that the basic products are now melded together in a way that was impossible some years ago. Exchange 2013 and SharePoint 2013 began this journey and now provide the foundation for a lot of what you see inside Office 365, including the provision of functionality to new applications like Planner, StaffHub, and Teams.
Office 365 and the current on-premises products share a lot of functionality. The on-premises products lack some of the features available in the cloud (like Office 365 Groups) but are more flexible and customizable because they have to adapt to different customer environments. In short, they are two peas from the same pod - different but similar.