We like to talk about the big reason why we don't have much of a presence in space as being political will or the lack of a cold war or even things like not having anything especially important to do.
I don't believe it. The real giant elephant in the room, that nobody likes to talk about, is the cost of getting up to space.
If you add up the costs of building and fueling a rocket, you quickly discover that the real costs involved are fairly small in comparison to the cost of a launch. There's maybe a 747's worth of kerosene in your average rocket booster tank. Building a rocket engine or a fuel tank is hard, but not excessively so.
One thing that keeps launch costs up is that you cannot build an assembly line. If I were to try and hand-build an engine for a car, you know it's going to be much more expensive than a mass-produced engine, even if it's got the same capabilities. If anything, the mass-produced engine is going to be more reliable and even higher performing because the assembly line can use sophisticated non-destructive testing and more carefully controlled machinery.
The other thing that keeps launch costs up is how much stuff is thrown away. The engines generally need to be able to survive at least a few launches worth of use if they are to be able to make it through the testing program expediently.
The problem is that there are a LOT of ways to solve this problem. Most of them require some degree of investment, but not an absurd amount of investment. Consider that one person's startup earnings from the dotcom boom is funding SpaceX.
The problem is that the degree of investment for most of them is large enough that most of them have failed, both privately and commercially. There are literally hundreds of companies that promised much the same thing SpaceX did that didn't even make it to the first flight.
There's a chicken and an egg problem. It turns out that this is less engineering and more market architecture. See, most of the possible ways to make launch costs go down only start to look good if you can cause the market to expand. Consider if I found a giant lump of gold tomorrow that was worth billions and decided to fix this problem. I'd probably pick the most likely to work solution that can fit within my available budget and start work on it. Let's say I told people I had money left to fly one hundred flights this year at an incredibly inexpensive cost per pound. I could launch every single satellite that was manifested for this year and only fill half my flights. It may take years for people to figure out and adjust to the new marketplace, much like it took years for people to actually figure out how to make money instead of burning investor cash on the Internet.
The biggest downfall is that we don't have a legacy of truly failed designs. In computing, we've got plenty of products that shipped and failed in the marketplace, thus you can often draw from their experience that certain ideas only sound good on the drawing board. However, if a space startup burns millions of dollars but never hits the marketplace, you can't really say that, were they to have actually launched a few times, if it would have worked or not.