Hello Davida, welcome,
I like the way you have been doing hands on experimenting. You'll end up going to college and knowing more than the teachers
I have no first hand experience but covered the basic theory when I was at horticultural college. I don't think there is a definite 'hydroponics is better than soil' answer. Horses for courses, what's possible ? what's needed? One should always go for the
appropriate technology.
But I'm sure of one thing, hydroponics is never going to replace soil as as the main medium for growing stuff.
Also the flavour component of our food is important and so much mass produced food (even when soil grown) seriously lacks taste. It's not just the variety of the plant that effects the taste but also the growing medium. Think of wines made from the same variety of grapes but grown on different soils. I wonder if any one is producing wine from hydroponically grown grapes?
Bringing degraded, polluted area back to health is possible as others have said. It takes time and effort to do but perhaps 'saving soil' is at least as worthy a cause as saving the amazonian rain forest.
Go well
><>