I love Isaac Honig, but I'm curious why he's on this list.
I've been told by an insider in the JM industry that Isaac Honig sells a vast amount of albums, far more than any other singer in his caliber.
Although he didn't specify a reason, I think it's obvious. The demographic he caters to often does not own computers or smartphones, so copying it is not prevalent there. He puts out an album once every 10 years (generally), and it's top quality, classic songs. Everyone in his demographic buys it, as well as many in the litvish world.