The bleeding edge of physics and other science and math if often just a lottery. You research something, show that it's probably correct even if it's not practical in any way, and then years later someone says "you know, if we just applied..."

Modern cryptography would be impossible without number theory, yet all the breakthroughs that made it possible took place decades and centuries beforehand. All they needed was "with a computer" for it to become vital to our everyday lives.