Seems like the real and hard truth is that, at anything resembling our current tech levels, human spaceflight just doesn't add much value compared to the massive, overwhelming difficulty.
We've sent hundreds of robots all over the place. To Mars, Jupiter, asteroids, comets, the outer planets, out of the Solar System entirely, as close to the Sun as can be managed, and everywhere else in between. For basically all of these missions, sending humans along would be 1000x more expensive, and the humans would be bored to tears for 99.9% of the time. For most of the rest of the time, they'd be relying on the same instruments as the robotic missions, as the environment is too harsh for anything else. So what's the point?
And who would we be sending? We could send super-smart scientific experts to maybe follow up on things a little faster, but it'd be a waste to have them sit around for years on the voyage back and forth. Or we could send more ordinary folks, who might not be all that much more capable than the robots we're sending now.
Sorry, it might burst some peoples bubbles of romance and sexy space adventures, but it mostly just doesn't make sense to send humans into space for the type of exploration missions we're doing. Maybe if we can send enough resources to actually have a colony on Mars or something, but we're not there yet.