We do have a lot of really cool technologies that could revolutionize how we generate power, clean water, and generally live.

But they are expensive, so they don’t get done.

We could have been running the world off of nuclear reactors for the last 60 years, but they’re more expensive than coal and gas, so we haven’t.

We could also have potentially had a giant solar array in orbit that beamed power down to the planet, which would have been built in the 80s and 90s. But we got the space shuttle instead, because it was cheaper and more feasible. Now the space shuttle was awesome, but it’s competing project was truly a leap ahead in space flight.

There are a few people that, according to blood panels, have been cured of HIV. But it’s a very expensive and painful procedure, as it involves a bone marrow transplant from a person that is genetically immune to HIV and is a match for the person that has HIV.

The technology is occasionally there, but it’s just so impractical to implement it at scale that it never happens.