> Would a detachable escape rocket + parachute be more efficient?
Only in the short term. Without retro-rockets to enable a soft-landing, you'd have to land at sea Apollo-style, and then you can't re-use the capsule because sea water is so corrosive. (Soyuz uses retro-rockets but the capsule isn't designed for re-use). SpaceX's goal is to have a launch system with re-usable first stage and crew/cargo capsules, which would significantly reduce the cost of getting into space.