I feel like this answer should have a giant asterisk by it.
Technically SCCM will never be cancelled because it has a massive install base for supporting legacy/traditional workloads. Tons of companies rely on it for this so it will continue to get regular updates, patches, and remain a reliable workhorse for a long while.
It will also never provide any real value to emerging companies not tied to tech-debt, nor do any function remotely as well as it can be done using modern apps/processes due to it being tied to legacy dependancies so it can perform those functions. it will, from this point forward, be a mountain of old ideas that smell a bit more like garbage every year.
There is, without exception, nothing SCCM provides that cannot be done better with other tools/methodologies unless you have that legacy ball and chain holding you back.
App Management? Most modern apps are either services hosted in HTML5 or can be neatly distributed via container structures like docker. The complex days of app sequencing are coming to an end. Done. Very soon docker repos will be the new Distribution Points, and users will simply browse from a landing page to all thier apps.
Workstation Config profiles? Why install and maintain a SCCM farm when you can just use a PaaS? Not having to config WSUS and configure update packages is worth it alone, plus the "internet first" nature means _zero_ needs for VPNs or other complex network design elements.
Compliance settings? DSC has that covered now and can act as a framework for things like Puppet, Chef, or the myriad of Azure/AWS hosted versions. Oh and DSC works better than SCCM policies ever did.
Imaging? Heck, MDT already does it better than SCCM anyway, and it's free. Better yet, get onto Windows 10 that overhauled the whole process. It's not that tough anymore. Want to image servers? Packer does it waaaaaaaaaay better and it's free.
SCCM is not going anywhere. Neither in the marketplace nor in advancements.
