That exact design is a dead end but no breakthroughs are needed for orbital spaceflight. See what SpaceX is doing with reusable rockets, for instance. And Space

That exact design is a dead end but no breakthroughs are needed for orbital spaceflight. See what SpaceX is doing with reusable rockets, for instance. And Space Shuttle, although economically unsuccessful, showed that material and rocket science from 40 years ago made it physically possible.