"I’m all for space stations to assemble deep space exploration ships. Just not as an integrated, necessary step for creating a moon base."

My point exactly. Adding an extra step, however otherwise justified, adds risk, time, expense and complexity to the process, but it does make it more flexible and adaptable. But a lunar gateway only makes sense for the lunar mission--it has no other application or justification. If for any reason we give up on the moon, or shift our attention elsewhere, Gateway will have to be abandoned, no matter how successful it is.

By moving the 'gateway' to earth orbit, you get a midway assembly station for much less cost and easier maintenance and operation, and in an environment where we already have lots of operating experience. And in the event we ever have to abandon or cut back our lunar presence, we still will have an asset that can be quickly shifted to other missions, like manned or unmanned missions to the rest of the solar system.

It makes no sense to assemble and launch a big, complex mission to Mars or the outer satellites from cis-lunar space, it makes much more sense to do so from LEO. The point I'm stressing here is that we should always engage in complex space projects with consideration as to how they may be employed in future exploration. 'Optimizing' for a dead end may be short-term wise, but long-term foolish.

Both the US and USSR managed their space programs tactically, but not strategically. They were more interested in beating each other than in a long term space program to move humanity into the solar system. Apollo, the Shuttle and the ISS were never designed for long term expansion, each step building on the previous one. They were all one-shot deals. China will not make that mistake.

Our next big manned project should be a permanent replacement for the ISS, in a high ecliptic orbit, with a view to use it as a staging area for future missions into the outer solar system. By 'permanent', I mean one which can be continuously upgraded as new tech is developed or old hardware is decommissioned. Yes, we have agreed on this before! The idea that the ISS is being scheduled for destruction because its becoming obsolete or worn out should have been anticipated. What a waste!

One feature of this concept is that the presence of a permanent functioning staging/repair facility in ecliptic orbit is that other nations will have a resource available to them (one for which we can charge them a fee!) they can use, allowing them to rely on our base as a spaceport to support their missions. This will encourage other nations, and private corporations, to get involved in their own space programs. The key to developing space is to manage it so everybody wins, not as a race with winners and losers.