While I mostly agree with what you've said in respect to a Mars base -- I think you are leaving out a critical benefit of these types of endeavors.
The technology invented and/or adapted to facilitate these enormous space projects is very often applicable in other fields or daily life.
Some examples from the past include metallic glass (now used in power plants), translucent polycrystalline alumina (now used in invisible braces), water purification technologies, the coatings used on launch pads was adapted for use in coating steel for high-rise building projects, etc. The list is quite long.
There are hundreds of spin-off technologies, many of which are used daily, which originated from various ambitious space projects.
The technology invented and/or adapted to facilitate these enormous space projects is very often applicable in other fields or daily life.
Some examples from the past include metallic glass (now used in power plants), translucent polycrystalline alumina (now used in invisible braces), water purification technologies, the coatings used on launch pads was adapted for use in coating steel for high-rise building projects, etc. The list is quite long.
There are hundreds of spin-off technologies, many of which are used daily, which originated from various ambitious space projects.