Lumber sizing

I am no expert craftsmen and this drives me nuts. When did 2x4 s stop being 2x4 s? You can head over to Wikipedia and get a run down of 'dimensional sizes' versus 'actual sizes' and a lame explanation as to why that is. Wiki says it has to do with planing and kiln drying. Well maybe, but I am leaning more to hogwash. There certainly is planing involved. I suppose kiln drying would shrink stuff, but you aren't supposed to cut timber until it is dry so shrinkage should be minimal. I suspect is has more to do with getting more boards out of trees and using planing chips for cheapass particle board.

I live in an 80 year old house. The 2x4s actually measure 2 inches by 4 inches not the 1 1/2" by 3 1/2" that you would get at a lumber yard. The trim pieces also measure out to actual inches. I have a number of 1 inch by 4 inch boards, but try and find that in a store !!!. Somewhere along the line it changed. Why can't the wood be sold by its actual dimensions? And why can't they accomodate the 'planing' and 'shrinkage' to result in accurately sized lumber?

I am trying to finish the attic in my house. I am wanting to do the trim in the same manner as the rest of the house. Fortunately the millwork is minimal but all the trim boards have nicely rounded measurements that used to be standard. I shouldn't have to buy a planer for this but I may.