Hi Mark! Thank you for the kind words.
You're absolutely right, none of this is going away.
I honestly believe that learning merely the basics is enough, because honestly, the buttons change, the look and feel changes, but the basic concepts of these devices and software has been the same for the last 20 years. They add more features, but even on a new device, no one needs to use or learn them all. Pick and choose those you think would be most helpful, and you're good!