Countries like China are finding that industrial espionage is more important than military espionage
This is true, but it has a very long history. There's a great book called "Secret Armies" by Bergier that has a history of it--like people trying to steal the secret of making silk, or glazing pottery, or making steel, that sort of thing. You may find the book in a library.
Bergier, IIRC, was one of the many scientifically trained people who descended on Germany towards the end of WW2 trying to pry out industrial secrets from companies like IG Farben.
In the 70s and 80s the Soviets targeted--"tasked"--people to find out or acquire very specific things--multiplane CNC lathes that formed the blades of extremely secret submarines, for example. It's not a coincidence that they also made their space shuttle a virtual clone of ours(I just read that the higherups believed the USA developed the Shuttle as a way to bomb the Kremlin from orbit so they cloned it to find out how that would be done!)
I remember a series of articles in Soldier of Fortune in the 90s tracking the growth of SoCal shell companies whose sole purpose was to find and transfer technology from the US ultimately to China despite official restrictions. Lots if them were centered around the Long Beach area pier that was rented out to a Red Chinese Army shell company.
Even though Wen Ho Lee was never found guilty of direct espionage it's hard to believe the Chinese went in a very short interval from very basic atomic devices to virtual clones of the latest US weaponry that were the result not just of lots of computer time spent on extremely complicated fluid dynamics problems but also special milling machines and manufacturing processes that are secret.(Ho wasn't a part of that, though, just the computer modeling part)
There's also the way governments will use businessfolk or scientists as "NOCs"--non official covers--to provide information they discover during their usual rounds: how many smokestacks, truck bays, production lines, how does a bank do a money transfer, what's of interest to the other side at scientific conventions,stuff that may be innocuous and perfectly legal but be part of a larger tapestry the agency is forming. I know high speed computing and modeling was a big target since it's a vital part of developing all sorts of aircraft and space stuff, as well as weapons of all sorts.