I somewhat agree. Facebook may not appeal much to people interested in let say space exploration or self-driving cars, but amount of engineering lessons learned

I somewhat agree. Facebook may not appeal much to people interested in let say space exploration or self-driving cars, but amount of engineering lessons learned by deploying a software at that scale is still invaluable. We are so much better at distributed systems, machine learning than we were, and that knowledge can be applied to other problems (and it is).