Yamaha is pretty "par for the course".... I believe the Tenere will continue getting older like the FJR (and others). In my opinion, one day they will change the dash to a full color screen with some type of Gorilla glass. Add a few new tech items to hook up to your phone / maps.... Probably be able to read face book on your dash on your next trip, LOL..... Add 1HP and maybe change the windshield or front fender plastic. With the FJR, there have been changes over the last ten years, but not a HOLY COW moment of changes IMOP, 95% still the same as the 2008
So, Probably the only changes until at least 2022 will be paint. LOL
On the other end of the spectrum, with designing, developing, and producing new bikes "almost" to fast would be a company like KTM. There model cycle seems to be crazy fast with style and updates. That can be a good thing and a bad thing just depending on who the perspective buyer might be. They find a need or a want in a motorcycle category and BAM !!! They have it out the next year. (basically)
The Super Tenere is a fantastic motorcycle and Yamaha will probably just sit on a good thing with minor changes over the next few [many] years.