what about starving kids?

That was a cheap shot that probably defeats everybody. If we are honest, we should admit that in practice most of us have priorities other than feeding starving kids. Some feelings of guilt are probably appropriate. But if someone were to come and take most of your money and use it to feed starving kids, wouldn't you object, and fairly?

We've probably both seen/heard how unsatisfied people in our generation have been with the lack of funding, and in the manned spaceflight sector, particularly.

Sure, and I've also heard people complain about slow data service on their cell phones, beach traffic on three-day weekends, and expensive beer at airports. I don't hear many people complaining about gunfire in their neighborhoods, inadequate supplies of canned goods, and unreliable hot water. I don't feel comfortable assuming that people with those complaints don't exist. I am very uncomfortable with the thought of forcing them to pay for research they may never even be aware of, even though my sister has never been bitten by a rat.

A scientifically-illiterate populace has no business solely dictating science policy and funding

So, do you say it is justified for others to dictate to the populace how their resources will be used to fund science (1) for their own benefit, or (2) for the benefit of others?

In the first case it strikes me as paternalistic and presumptive to say that the illiterates will definitely benefit by having their resources managed by outsiders, and that they would definitely get inferior results by managing their own resources. In the second case it seems uncomfortably akin to simple theft.

Your investment math is interesting, but still makes assumptions that I don't necessarily agree with.

That's a fair criticism, but the biggest assumption I made was that your speculation of an eventual energy payoff from exotic research would come true. My assumption of the value of this payoff also, I think, favors your side.

My joke about waiting to buy the energy from Elon Musk conceals an important point. Allowing people to risk their own resources seeking potentially valuable energy sources means a lot of them will fail (perhaps even coming to ruin) but also that many more possibilities may be explored. Society's "managers" don't have to pick the right one. Maybe Elon Musk will hit a dead end, but someone else will find the secret of cheap, clean energy.