Ahh, facts.....they are so inconvenient and hard to come by. However you young whippersnappers, the innerwebs have this new tool called google. So I found the site of the European Monitoring Centre for Drugs and Drug Addictionand they had an article on just such a topic.
They said a number of interesting things
1. it's almost impossible to measure THC accurately.
2. %THC is just one component of potency
3. The everyday dope you buy from a dealer hasn't varied at all over the years.
4. Some indoor strains are indeed more potent, but it depends on a lot of things...like the skill of the grower, genetics, lighting etc.
5. THC fades rapidly with age.
6. Different labs will measure the exact same sample and come up with completely different results.
Regarding "state of the art hydro systems" perhaps not, although I seem to think we did. Regardless, we did have this thing called "soil" and it worked out pretty well. It still does.