We physicists, when calculating when we will attain type two or three status, only assume that our energy consumption grows at around three percent per year. Even though this growth rate seems very small, over thousands of years, you can calculate that we will have the power of a star or even a galaxy. The Earth as a single planet may not be able to sustain this growth over thousands of years. Therefore, we may have to terraform nearby planets in order to maintain this growth rate. Personally, I don't believe we should have a crash program to put men on Mars.
Robots are cheaper, and better.
However, over thousands of years, it may become feasible to terraform Mars. Yes, there is time in space. Some people have written that time does not exist. They are probably quacks. We scientists believe that any theory should be measurable and testable.