[M. Dodge Thomas]

The question in such cases isn't "Is it worth doing?", it's "Given that we have finite resources, is it more worth doing than something else".

IMO in the case of manned exploration of Mars, unless you put a very high "non-monetary" value on "being there", the answer is no: it's easy to think of more productive scientific, economic and military uses for the money.

[Fitzcarraldo]

The question in such cases isn't "Is it worth doing?", it's "Given that we have finite resources, is it more worth doing than something else".

The Moon is a diversion on the critical path to space resource self-sufficiency beyond Earth. Mars has all the components, in large enough quantities necessary to sustain an independent human colony without resupply from Earth. The Moon cannot ever hope to match Mars in terms of resources and hence will always be a resource sink in space operations.