Part of the renewed interest (as stated above) is his fascination with Stephen, I believe? Which starts as a result of his loitering around Lady Pole. From then on his travels to and from our world are pretty much exclusively driven by Let's-Make-Stephen-The-King machinations or a direct result of being summoned (poor Arabella). Basically it takes actual sustained motivation (which fae appear to lack) for him to be bothered to leave faerie in the first place. Obsession appears to be a prime motivator.