Nice points.

I'd definitely agree that it's not salesmanship, it's a different (and kind-of) related skillset.

Apart from anything else, direct mail and web copy are very one sided - there's no way to figure out the reasons don't buy which I guess is why even 2% is profitable although higher rates are definitely possible.

Grab attention - yes, but in a way that isn't in your face. You could be offering me $100 free but chances are I'd have clicked the "X" or "close" button before I even read that far. And even if I did read that far I'd be trying to work out what the scam was.