If the only way I got above 8GB is by leaving applications open and letting them idle, that would be lazy. But if I'm actively using each -and closing documents and programs which I feel I'm done with, that's not laziness. I'm just using the equipment I have to its potential.
And you're not taking into account the increasing requirements of programs. For example, Photoshop CS6 requires a much more powerful system than Photoshop 6.0 requires. At one point 1GB RAM was more than sufficient for even high-end desktop computers - now phones are starting to struggle with that little memory. So at some point in the future - one may very well need 64GB to efficiently perform the tasks expected of him/her. That's just the way it is. If it wasn't that way, then 640k would likely still be more than enough for all of us.
Especially with everything moving to HD, 4K, 3D, super resolution, frame per second, fully packed content.