First, I’ll admit, after rereading, a poor/uncharitable first read of your position. Sorry for that.
But I would still suggest your complaint is about some economist rather than economics as a study or analysis tool For example, “If anything, the value of labor goes UP, not down, with population! E.g. dense cities are engines of growth!” fits very well into economics of network effects.
To the extent that the economists can only consider AI as capital that’s a flawed view, I would agree. I would suggest it is, for economic application, probably best equated with “human capital”—which is also something different than labor or capital in classic capital-labor dichotomy.
So, in the end I still see the main complaint you have is not really about economics but perhaps your experience is that economists (that you talk with) might be more prone to this blind spot/bias than others (not sure who that population might be). I don’t see that you’ve really made the case that it was the study of economics that produced this situation. Which them suggests that we don’t really have a good pointer to how to get less wrong on this front.
I don’t think selling or buying votes is a good solution. There is a reason why we have multiple forms of social institutions: they solve different types of problems using different types of tools. If you think the problems of governance and policy are solved via a market mechanism I think your first task is to show why the market solution never emerged in the first place. But I think if you want to go down that path why stop at votes, why not take David Friedman’s approach of a market anarchy where government largely doesn’t exist but private solutions provided in a competitive market setting do.