That's true. However, I think most of the copying that people are trying to accomplish is usually a script or something similar that is pasted by one person. That means it's already aligned correctly for column selection. This also would not require changing the a lot of scripts out there, whereas requiring changes to /echo would.
There is a benefit to having columns, but at the same time, that benefit is rarely needed by most people. Most of those who need it infrequently could do just fine with column selection. So it would really only be a noticeable benefit (in comparison with column selection) to a very small number of people. And that would be at the cost of a LOT of scripts requiring updating to handle any /echo changes. I just don't think the good outweighs the bad. Especially when you can get most of the good out of column selection, which doesn't have any bad side to it.