Yes, espionage has existed for as long as we've had governments, if not longer.
I think the key point of this article is about how China's military is conducting espionage on commercial, non-military entities for the gain of its own commercial sector.
I haven't heard of the US government going this far. I certainly have heard of the US government sharing information about military and intelligence technology with corporations, but I haven't heard of them doing so for other technologies, outside of times of all-out war when learning, for instance, how the Axis was producing synthetic fuel would be shared with US corporations.
Commercial entities certainly spy on their competition. They will quite happily analyze their competitor's products and try to use whatever they learn to the greatest extent possible. That's different, than, for instance, the German government tearing down a Japanese car and then telling MB
/VW/BMW/etc what they've learned.
As for the difficulty of security, you don't have to go very much further than the head of the CIA
's affair being discovered via email tapping to see how even very intelligent people do very stupid things.
Good security is possible but quite expensive. You really need to have a lot of defenses, and your own 'tiger team' actively probing the defenses as well as the employees. This is expensive and can make some Perfect security is impossible. All it takes is one mistake by one human and it's all over.