nations have more money and resources
No, the citizens
of nations have money and resources. Waiting for "the government" to undertake the big projects means they will never be done, or done without any vision and usually in the most inefficient manner. Governments spend, they don't invest
. Private investors will be looking to fund bases or colonies elsewhere for ulterior motives, not simply for the end purpose of planting a flag and then forgetting the whole enterprise for another century.
Not sure what your first point is. As to the second, you still haven't explained how private investment will get any return that compensates for the hugely expensive outlay.