I recently got into the custom home building business. It might just be the way that I'm interpreting the comments, but there seems to be some confusion on this thread. There is a big difference between Solid Core doors and Solid Wood doors.
I can get Masonite Brand solid core doors, prehung for about $90. The equivalent solid wood door would be about $250 (poplar rails and stiles, MDF panels).
A casual observer will think that they are the same, but upon closer inspection, the detail on the solid wood door is much better, and they function and feel better too when you use them. The solid core doors are generally a molded hardboard (masonite) material and the door is then filled with some type of corn husk material or something like that. The downside will always be the molded look, as they lack the crisp seams and joints of an assembled solid wood door.
As to the question of whether or not time = $..... Time that would've been wasted watching TV is not worth anything. If the time would've been spent making money or contributing to society, then it becomes a consideration.