Spending a thousand or two on a computer is a hell of a lot easier to justify than spending several hundred on a harddrive. Particularly when you can find less fancy harddrives for a fraction of that. SSDs are far more of a luxury item than laptops.
Agreed. My lizard brain tells me that too. When we buy a faster processor, we are valuing our time against the cost of the processor. I just have to convince the lizard inside to do the same with disk wait times.