Or, in my words: System trade off studies are not for sissies.
Scott Lowther posted a couple of slides from a November 2011 presentation on NASA's Space Launch System. The first displays the configurations that were considered. Unless you have worked on a trade study for a large system, you won't appreciate the work that goes into such a thing. You not only have to quickly put your arms around things like development costs, recurring costs, performance, reliability, etc., etc., etc. You then have to mash these disparate things together using a mix of analytic and subjective methods. Finally, someone comes out of the woodwork and asks: "did you consider xyz". I am just happy the things I worked on never got the Congress-critters attention. But, all that aside, I love rocket p0rn an think this is most excellent motivation for sport rocketeering.
The next slide presents the range of proposed and fielded launch vehicles, from Xcor's Lynx to the proposed SLS Heavy. Yes, I am convinced that NASA's is bigger than yours but, really, does size really matter? Scott points out that most people don't think SLS will ever happen. Besides the pesky issue about the lack of money, Scott also points out a potential chicken and the egg condition. Since there is no identified mission requiring the SLS, then there is no political will to build such a thing. And since we don't have a suitable launcher, there is no political will for a manned Mars/Moon/asteroid/L2 mission. I can't help feel that a big piece of the puzzle is that politicians are using NASA as a pawn in their game. A pawn with a reset button that will likely be pushed every four years. But, this is another cute slide. Long live new-space!