The 80D will be just as outdated as the 6D in 2-3 years! Unless they happen to release a firmware that gives it new functions / settings. Which is highly unlikely. The technology will age the same in both cameras. If one is better than the other now. It will always be better than the other! Now in near future 90D may be better than a 6d? But that is an unknown at this time. But between the 80D and 6D. I believe the 6D is the better camera for output. Feel and ergonomics, do have a big impact on the user though. And if you like the touch screen options of the 80D. It just may be the better camera for you. It's not like the performance of the 2 is night and day. Just one is better than the other in terms of output.