Elon Musk doesn't seem like the easiest person to work with, but I'm having a hard time thinking of a more accomplished human.
I mean, I guess some people here subscribe to the notion that space travel is imperative for human survival. In that case, you might argue that each step towards it is more valuable than anything else that does not immediately push towards human space travel. Human space travel will save humanity, your piddly vaccine only saves a couple of hundred million people. But that seems a bizarre argument to make (and maybe that's why one really makes it).
Edit: -3 in one hour? Wow. For what it's worth, I made this comment in good faith.
Consider something such as a weather satellite. What goes into such a system? What inventions and breakthroughs are responsible for its existence? Things like CCD imagers, micro-chips, and, yes, rockets. Are the inventors of such things savers of lives? Surely yes, because it is through weather satellites that we are able to track and monitor hurricanes, typhoons and other severe weather phenomena which historically have been great killers of lives. Today hurricanes do not hit land by surprise, we have enough time to warn people so that they can evacuate or hunker down. Over the years this has saved perhaps millions of lives. Are vulcanologists life savers? Sometimes they are. What about automobile manufacturers? Well, without automobiles it would take a lot longer for EMTs to get to people who are injured and a lot longer to get them to a hospital, so a lot more people would surely be dead without automobiles. If you were to see a construction worker digging up the road to work on the sewer would you think of that man as a life saver? He most surely is though because clean running water and sewer systems are some of the most effective methods of reducing the spread of disease. That man isn't just digging up the street he's helping to keep you free from cholera, as surely as any doctor or medical researcher would.
Reality is a lot more complicated and intermeshed than a naive, simplistic interpretation would indicate. What figure from, say, the 17th century is most responsible for the greatest reduction in untimely deaths since then? Such a question is almost impossible to answer.
But more than that, life is about more than merely living. This is the fallacy of Maslow's hierarchy at play here. The idea that an individual who is ill, hungry, in danger, or impoverished must necessarily forgo self-esteem, appreciation of art, romance, and intellectual pursuits. That is a backward and harmful way of approaching the world, whether on an individual level or on the scale of all humanity. Yes there are great problems in the world, we are ill as a people, we are hungry, we are not safe from violence and war. But should we shun poetry, music, and science for that? It is often through introspection and art that we can gain a better understanding of our fellow humans, that we can set aside hatred and bigotry. It is often through the pursuit of science and engineering that we find better ways to treat and prevent disease and to feed the hungry.
So I would say that we can and should strive toward putting humans in orbit and on Mars and it is just as noble a thing to do as curing disease or feeding the hungry. Because it represents what humanity is all about, pushing frontiers, exploration, knowledge, adventure. It is those things which make life worth living and give greater potency to more direct efforts of saving lives (just as the existence of art, food, and music do). And they also give us new perspectives. The photograph of the Earth from the moon by the Apollo 8 astronauts has been enormously inspirational throughout history, for example. Perhaps along the way who knows what new technology will come about. And, of course, more than likely we will develop the technology to divert asteroids away from Earth (perhaps saving billions of lives) and also make Earth a multi-planetary species, which could save human civilization from utter annihilation at some point.