The "interactive debuggers are useless" idea reminds me of how the Greeks felt you could think through any problem if you tried hard enough, and that experimentation wasn't required. But, as Mike Tyson says "everyone's got a plan til they get punched in the mouth" 
When they say “hard enough” they mean “long enough”. When talking strictly about productivity, you want the shortest path to the answer. Why spend hours thinking when a debugger can show you your mistake in minutes?
