Yeah I wish he had elaborated on that point. What are they doing to court those sellers and most importantly, why? Surely they know that their reputation is going down the tubes. Are they just so dominant now that they don't care?
As long as Amazon has their fulfillment and delivery network, I don't think they'll ever be replaced by AliExpress (in the US, at least). I've never seen anyone delivering packages in an AliExpress van :)