I have recycled my soil since 2007, when I moved to Costa Rica. I use three piles, although I don't go through the amount of soil you do I still use 30 to 40 gallons a month. I remove the rootball which goes to the compost pile and place the soil into the first pile of soil. The first pile gets all the new compost mixed into it to go along with the old soil. The second pile which usually has a few months of rest gets veggie scraps mixed in to feed the worms and keep the micro beasties happy. The 3rd pile is the one ready for use.
Any new soil or amendments go into this pile, black tierra, bio char, woodash, etc. The soil has gotten better, meaning richer, more moisture retentive and many many more micro beasties. This system is just basically substainable ag practices used on many organic farms, which I used when farming and brought down to a small scale. Is it a lot of work, yes, but there is much less work involved during the grow over constantly mixing nutes and other additives many must add to their grows.