It takes time to vet, test, and build things, especially when representative government and massive land usage planning is involved. Much of the tech in modern

It takes time to vet, test, and build things, especially when representative government and massive land usage planning is involved. Much of the tech in modern airplanes is still from the 1950s and 1960s. The tech developed in the 2020s and 2030s will be in the trains of the 2050s-60s.