I've never seen a purely theoretical solution work the first time it's applied in practice, even in the simple, straightforward context of programming a compute

I've never seen a purely theoretical solution work the first time it's applied in practice, even in the simple, straightforward context of programming a computer. I think the word "invented" has to mean something more than "proposed and refined a theory without any successful real-world applications". Furthermore, Marxist theory has been tested. I think it managed to turn out worse than capitalism, which is quite an achievement.