yep and just from seeing him and Anton hanging out, I am pretty sure it's still growing. The craziest thing I've seen in a collection is Anton's though, maybe because I get to see his updates more than Del sorta hard to trump Jim's Executive desk as a display item.
Probably hard to confirm a 'King' collector since all the premier league have pieces and specialities the others don't have. For me the key attributes are the quantity, condition, and inclusion of rare pieces. I had reached 1000+ pairs mostly everything mint but always felt I could never keep up and have enough. A top collector of anything will be always thinking of what they don't have rather than so much what they possess which drives them on to collect more and so they never feel truly content. From my experience I think the absolute top collectors are Anton Sy, Joseph Smith, and Nike Nickel.