Only a government that prints money can afford this old-school approach which wastefully expends boosters and upper stages.
No government could have marched European civilization across the US continent in the time frame it was done. Only in the name of commerce (mostly) could it happen. No government designed or built the prairie schooners thankfully; imagine the overweight monstrosity a government agency would have come up with even in mid-19th century. It was done by entrepreneurs who had to be competitively sensible.
No government agency will produce self-sustaining off-world human civilizations. It will be done by entrepreneurs who don’t throw away their equipment after one use.