Here is a possible timeline for the emergence of a true space age over the next 20 years.
In 2017 and 2018, we see Spacex complete the development of the Raptor engine and the launch of the Falcon Heavy.
The Raptor has about four times the thrust of a Merlin 1D engine.
Starting in 2020, Bigelow expandable space stations will be launched. The current plan is for two BA 330 station modules to go up in 2020.
Leveraging Robotics will be a very important accelerator in the industrialization of space
Using Spiderfab robotics kilometer or larger structures will be built. This can be used to produce megawatts of power.
Instead of mining the moon with people. Moon Express plans to mine it robotically for water ice for fueling space industry.
By 2027, we can have
* highly efficient and low cost launch with fully reusable rockets
* water ice mining from the moon and other resources from the asteroids
* Robotic and teleoperated construction in orbits, moon and near earth asteroids
* expandable space stations
* construction of large telescope, solar power and other structures
Critical space costs could drop by 100 to 1000 times.
Lower cost reusable launches will greatly lower costs
Water and other resources from the moon will lower costs
Capabilities will ramp up and further lower costs.