I thought that the shuttle never lived up to its promise as a low cost recyclable launch carrier. It was planned to launched every month or so, but this was soon shown to be unrealistic. After the first accident the shuttle lost much of its commercial (and even military) deals and the space station was thought up to give it a purpose, since it hardly had one.
A recyclable launch vehicle is questionable in human space flight, due to the fatal effect of any mechanical error. The maintainance becomes so elaborate that it is cheaper to build new and simple launch vehicles from scratch. The stresses of launch are immense on any vehicle structure and in such a high tech field, reusable crafts are just not feasible. The original idea was a low cost "bus" that would ferry people at will. The bus became too elaborate.
I think the trend in "single-use" technology is now everywhere. Try having a digital cam repaired. Maintainance is more expensive that production line building.
The design to attach the passanger vehicle right NEXT to the main fuel tank is probably also not ideal (in case of a bad malfunction or even just some foam). No emergency rocket to pull the shuttle clear from an exploding main tank like Apollo had etc.
I think it is an impressive vehicle, but has fundamental flaws. NASA should focus on new rockets and I am sure they could design some great ones.
The shuttle flying is more to do with demonstrating that the US still has human launch capability (since currently the chinese and russions do).
I realise this view may offend, and I do see both sides of the story. Always loved what NASA has done, but trying to save the shuttle is not a good idea.
