Let's review:

Public support for manned Mars flight is too low to enable go it alone flight.

The launch costs are too high, no matter what kind of fantasies one wants to engage in.

What the public does expect is detection and defense against the next impactor.

To our pleasant surprise, detection is best and only reliably done from the surface of the Moon, due to the frequency of
COMETARY impact and small comet fragment impact.

Those systems in turn might make possible manned flight to Mars, but Mars is looking less and less Earth like all the time.

In any case, the Moon gets developed - if not by the US, then by China, or perhaps by some coalition.