Why go to the Moon again?

This is a continuation of a thought which I had recently and earlier today.

If you were to argue for the economic point of view only, consider this:

escape velocity from the Moon:  5140.8 mph
orbital velocity around the Moon:  3682.8 mph  ( I'm guessing here because this source appears incorrect)

That compares, respectively, with roughly 25,000 mph and 17,000 from the Earth.

Also Mach 1 defined:  This is 1,236 kilometres per hour (768 mph), or about one kilometer in three seconds or approximately one mile in five seconds.

A performance point of reference: a SR 71 "Blackbird" could fly at Mach 3.3   You would only need about Mach 2 additional speed for orbit and an additional Mach 2 for escape velocity.  A lunar module could reach lunar orbit (Apollo era).   What you would need for lunar orbit doesn't amount to that much in comparison with Earth.

The point being that, if you wanted to do human exploration of the planets, you can first learn how to survive on the Moon, and then use the Moon for your launch station.  If you can survive on the Moon, you can supply your astronauts from the Moon.  The only additional requirement subsequently, therefore, will be in getting a crew from the Earth to the Moon.  From the Moon, they can get to the rest of the solar system.  That could be an economic rationale for a Moonbase.  It would be a launch facility in its own right.

In economic parlance, you will be leveraging lunar resources.

By launching from the Moon, you improve the economics of human space exploration.  It would take an initial investment, but once in place, it will improve your capabilities in space by reducing its cost.

Politically, it is hard to see how this works because there is no constituency on the Moon. Therein lies the problem. However, consider this: the Moon's launch facility can itself be leveraged for additional development of other industries that can be started on the Moon and beyond. And that, I would think, would be the whole point. In other words, a constituency can eventually be developed in connection with this since it will require support of some kind.