So what makes you think that people just use this machine to run MS Word. People want the most powerful, fastest, and most useful computer they can get in the smallest package.
Laptops of today have more storage, are faster, and have better GPU's than ultimate diesktop pcs of ten years ago. Those desktops were used to make movie graphics, run simulations, perform 3D ray tracing, use photoshop for intensive graphic manipulation, etc.
Sure battery life is important but a modern processor architecture, faster bus speeds, better memory management, faster memory, better gpu, are equally important.
It is difficult to project 5 or 10 years into the future and see exactly what apps people will want to use on ultra portable systems. So you might as well advance the entire system because more likely than not you are going to need it.