feasible near term Venus settlements?

[Rynn]

The original cost estimate for the Apollo Program was $7 billion, so using the same degree of inflation, Horizon might have ended up costing about $21.8 billion; of course, being a military program, getting the necessary funding would have been far easier than for NASA to get funding for Project Apollo, and any additional cost overruns might have been covered by taking funds from other DoD programs (it would be difficult for an outsider to discover the magnitude of any additional overruns, as that information would likely be classified as a matter of national security). The upshot is, while Apollo left behind a half-dozen Descent Modules, various bits of equipment, and six flags (which have since faded due to exposure to solar UV radiation), Horizon would have left behind a functional manned lunar base (with all that implies, such as a continued raison d'etre for maintaining a man-rated Earth-Moon transportation system, much more lunar surface experience, and, possibly, increased interest in researching cheaper/more efficient ways to get to orbit).

I'm still very skeptical, especially of the idea that the inflation in cost would be comparable. Project Horizon was estimated to need 61 Saturn I launches and 88 Saturn II launches just to build the base. In reality only 10 of the former ever launched and none of the latter. The Saturn I cost a billion dollars itself, I don't know how much of that was the launches themselves compared to the R&D but I'd be shocked if four times as many resulted in a negligible increase in cost, same for the Saturn II.

Actually, while most people probably would say they'd rather spend the money on Earthly concerns, it is almost axiomatic that they would still complain if you actually tried to spend the money on those things.

I disagree, I've never heard anyone express an opinion like this unless they were an ardent space enthusiast. The closest I can think of is seeing comments on space news articles where people opine that more funding would be good but many of those fall into the above category of people and/or don't concern the level of expenditure we're discussing.

If the money were magically to appear as unallocated funds on the budget, you can imagine the scramble as legislators vied with one another to assign them to one or another pet project, and/or to refund the money (or some part of it) to the taxpayers as a way of generating the good will so necessary for their re-election campaigns. If one were to devote tens or hundreds of billions of dollars to infrastructure, education, health care, etc., it would immediately engender two problems: 1) it would set up an expectation that such levels of funding would constitute a "baseline" that future levels would at least match if not exceed, and 2) it would lessen the importance of the lobbyists for those interests (and thus reduce the amounts said lobbyists are willing to pay for "access"). So, expect such a sudden windfall to be spread out among so many programs that there isn't the slightest danger of the money being used for substantial improvements.

Your conclusions only work if you assume a magic lump sum of money appearing. In reality that isn't going to happen. Also what makes you think that spreading out the money wouldn't result in substantial improvements? With very few exceptions if $X billion of new funding was announced for science I'd rather see it fund thousands of smaller projects to the tune of $1 million than one large project.