"... we might be as ignorant about our surroundings as we were 50 years ago, when astronomy texts still included the debate about the craters of the Moon being impacts or calderas, and the 'vegetation' hypothesis about Mars' seasonal changes. We might still be imagining jungles beneath the clouds of Venus. And we would know nothing else about deeper space than we could glean from Earthside optical (and radio) telescopes."

I have nothing against robots, but don't think it's in our interest to fill the universe with them, exclusively. Robots are particularly good if you have a limited purpose for them. For instance if you refuel a spacecraft robotically on Mars for the human return trip, that could be a good thing. I also think using teleoperation on the Moon for mining and other things could good way to lower cost and lower risk to human life. For example, 95% of lunar mining operations could be done by people living on Earth.

"All thoughts of the glory of personal human exploration aside, we receive a lot more science for the dollar from "robots"."

Glory isn't worth much. I can get glory from a football game. The value human exploration is exploration- to find out things which can be exploited. And "personal human exploration" is something tourists do. The Apollo crews were mostly working, which doesn't mean they didn't have any fun, or have some nice experiences.

As for science for the dollar. Space exploration isn't all about getting science for the dollar. If space were all about getting to point of having say a million humans per year to visit the Moon or elsewhere, that might be somewhat important but if that was all there was, it wouldn't worth much, but it be worth more then most of the science you could get.

Though obviously science is needed before one could have a million people per year visit space. But all the science one could want and all the tourism you could want, added together doesn't amount to much. But both would enable other things. I.e, if you have a number people visiting the Moon one will probably have some people living on the Moon to provide service for the tourists- so we got something else, space colonists added to the list.

The colonist might work in hotel, they might work providing rocket fuel needed for return to Earth, they might grow some food, so tourist can at least garnish their meals with stuff grown on the Moon. But even with all that, isn't worth much.

How about adding 100 colonists living on Mars doing things like people currently doing at the Antarctic with of course some more "serious" tourists also going to Mars. Still including everthing so far it doesn't amount to much.
Though obviously with all the above, one could do a lot more science- a huge radio telescope, on the Moon might affordable, as one example, but couldn't list all the stuff one might do in regard to science. But still it isn't worth too much.

What would worth a lot? Well, something that is of some use to Joe six pack, or the people who supporting all this "effort". So, getting electrical power from space, could be useful. Lowering the cost so that going into space is a cheap as a trip to Paris; would be valuable- and/or traveling around the earth [suborbitally] faster. How about products made from manufacturing/processing things in a vacuum. Now, you getting into the realm of something which worth it. Then of course one gets to the point where Earth is a part of humanity perhaps still a major part, other parts are on Mercury making huge energy intensive "stuff" things that make our biggest things we currently make, seem tiny. people could living those wheel worlds- earthlike conditions. Etc.

All the above involves humans and of course lots of robots- far more robots then we would ever send from earth into space.