I think you highlight the right issue, and this really shows the difference between simply having a site and directing traffic, or having a LIST.

I don't know how many subscribers you could of received, impossible to say really, but I am sure that yes you would of made more sales with a list... and you also could of promoted another launch to that same (but bigger) list this month... and next month... and...

I would recommend anyone and everyone to start niche list building on their sites, I have seen it from both sides - as a vendor my list owning affiliates send 10x more traffic and make 10-20x more sales than anyone else, and my own lists make very healthy profits for me and allow me to JV with some very successful people... it's win-win... its ALL about the list.