I don't see that in my experience. Most of the biggest and best farms I have visited were all soil grows....and I've visited a lot of grows in my time.
There are some benefits to growing hydro but there are also drawbacks. Any system failure can reek havoc on your entire crop.
The genetics and grower talent account for most of the the thc content in my own experience. Growing for over 15 years in Canada and Thailand have led me to that conclusion. Also I have many years of extraction experience that pushes me to think that way. I could be wrong maybe there is some science out there that would give us both a conclusive answer.
@SamuiGrower might be able to help on this. Hes a plethora of great knowledge.
Plus soil grows just seem to taste better ......but that my own bias 😆