It has to be true that if you remove something from anything, the anything has to eventually run out of the something. Did Einstein say this first???
The real question is about how long it takes for the depletion to be significant. My impression was that Aquasoil would be good for a few years, not just one year. I would never pay that much for a substrate knowing I would need to replace it in a year if I wanted to keep the same plant growing qualities, and plant growing qualities are the only reason I would be buying it. If I have to replenish the nutrients why not just use pool filter sand? Much better economics.
I agree any of the inert stuff (pool filter sand, sms, turface) works just as well with the proper fert regiment so it comes down to if you want the exact substrate and ferts that he uses or do you want to stay in the less expensive group.
I haven't tried the ADA products yet tho once we are in the new house and my fish room is complete I'll setup a 10gal with it just to see what all the hipe is about.