David-you do bring up a good question that I get in my ArcGIS Pro classes and Technical Workshops all the time. Is ArcMap/ArcCatalog going away? And is ArcGIS Pro the replacement for ArcMap? The short answer is no. ArcMap/ArcCatalog will be with us for quite some time to come. There will be an ArcMap 10.5. There will be an ArcMap 10.6 (or will it be 11.0?) The ArcGIS for Desktop deprecation schedule shows ArcMap 10.4.1 retired Feb 1, 2022. With ArcMap 10.5 and later, those dates will be added as the software is released.
Now with that said, Esri is investing/developing heavily into the ArcGIS Pro application. The next release of Pro 1.4 will bring near ArcMap equivalency to the Pro application. ArcMap is still in the development cycle for bug fixes, some updates, some new functionality. But Pro is where the development is focused.
ArcGIS Pro and ArcMap can run side by side on the same machine. To my knowledge, there is no plan for a Pro "ArcCatalog" as Pro is the fusion of ArcMap, ArcCatalog, ArcScene, ArcGlobe, and City Engine Runtime.
Esri understands that many of our customers cannot upgrade quickly to new technologies and value the ArcMap platform for many workflows. As such there are no plans to discontinue ArcMap anytime soon. ArcMap will be with us for years to come.
Keep in mind, I'm an Esri instructor and am not privy to the inner details of development or corporate decision making. This is based on my conversations with Esri Staff, some of whom are on the Pro Team.
Hope this helps clarify.