>Does it? There are plenty of disastrous decisions in the last 70 years at the level of major policies.

"In the last 70 years" does a lot of work in your argument, as it includes a full blown revolution, counter-revolution, eras of political turmoil etc. How about the last 20-30 or so years after things stabilized there?

Also, isn't the point of the parent that it's OK to have "plenty of failed projects", as the question that starts this thread is about our inability to run political experiments. Obviously some of them will fail - that's what experiments are made to test, not guaranteed success.