I'm neither a scientist nor an economist, so don't start asking me about the benefits to third world countries. Personally, I'm satisfied with taking an educated guess that there would be some. And unless you are one of the above, don't start pretending you know either.
I'm talking about the nature of such an endeavor. I don't know about you, but in the better, brighter future that I wish for, you've got countries trying to get away from nationalistic chest-beating and you've got humanity working internationally to advance our race.
I don't know about you, but I don't want to spend th rest of my days living in a Cold War environment that has become the normalcy. China, Japan, the EU, the US, Russia and possibly the likes of India and Pakistan, in constant competition and constantly trying to sabotage each other's effort at, well, everything. Thats like cars at a racetrack trying to win the race by bumping the others into a ditch. You end up with one winner, but everyone else is worse off.
Why does there have to be a race? Why does one country, your country, have to be THE BEST. Who cares. Why do you want to be able to look down on everyone else 'cause they don't have a space prgram or running water or 120 TV channels. How about, instead of spending $500 billion yearly on tanks and guns, the US used that money to feed, clothe and educate every person who needed it. If you did that, do you think you'de have *anyone* wanting to attack you, kill your citizens, destroy your buildings and so forth. Hell no. Same goes for China, for Russia and many others. Feed your people, give them healthcare, let them live life without having to work 15 hours days in order to get a moldy piece of bread so their kids don't starve. Buy a gun and you can keep one terrorist from blowing himself up. Buy a loaf of bread for 1/1000th of the price, and you get the same effect.
How long do you think humanity can keep this up, this struggle for supremeacy over everyone else? 50 years? A hundred? And then what? Let the age of the Empire pass, its a thing of the past. You've got one world. Thats really as simple as it gets. One world, and one people. You think that some poor ****er in Somalia doesn't have the same hopes and dreams as a soccer mom in California? A line on a piece of paper dividing the world means nothing. Its an illusion, designed to keep humanity fighting amonst itself so that a handful of people can wield ultimate power. This military, economic, political, cultural competition is not sustainable. Sooner or latter, its going to end in disaster.
****, that sounds very idealistic, but if you never strive for better then you have right now, you're never going to get any better. Strive for the best and though you will not reach perfection, you will progress. And no, I'm not a hippy

:D