People make money using Office, you don't earn money on Netflix and Flappy Bird or whatever.
You might plan to keep your Macbook for 5 years, that doesn't mean it's going to happen, look at the number of people planning to sue Apple over the Macbook problems.
I take your point on the MS Office being able to make you money. Very good one. I also take your point on the 5 year plan being subject to accidents and defective parts. This conversation is edging dangerously close to comparing costs of Macs verses PCs so I think I'll drop it here. That's another thread.