Computers are disposable commodities. Buy one use it for a few years and upgrade. They are tools like a welder that buys welding rods, or acetylene tanks.I'm sure Tim Cook's tasks could be done on the 2015 base Macbook.
But for people that *are* paying $1199 today to get an experience capable for office/CEO tasks, I expect them to want to hear that it will be fine to use up until the at least the year 2029.
Let's see how well an 8GB machine fares then.
I swap out about every two to three years, suits me just fine. Buy a new one hand me down to one of the kids my still functioning unit and move on.