Why would we want to go back to 1970s technology?
Capsules are not 1970s technology. They are a case of form following function. A winged spacecraft like the shuttle could only operate in low Earth orbit, with relatively low re-entry speeds. Try to take one somewhere like the moon (or Mars) and it would burn up at the higher re-entry speeds upon its return. Capsules are the ideal shape for re-entry from longer-distance space flights, simple as that.