I think a big part of the problem is the site itself. When you go to ticketdisaster or through the team website and try to buy individual tickets, only the tickets the garden is selling come up. You have to find the box for resale in a drop down menu, and click it for the seats to come up. Those who aren't all that familiar with the site or only buy tickets on occasion are not likely to realize what to do.
This is a huge part, before the season I sold a ton of games because they all showed up, now you turn it off and on. While I understand they want people to see their inventory first, I feel like it's almost misleading the customer. By calling an item "resale tickets," to me, that sounds like tickets that will cost me more than what ticketmaster is charging. The name alone implies these were purchased for cost and being relisted. Whether that's true or not is fine, but that's what is implied, you will be paying more for these. When they turn it on, suffice to say, that's not the case 100% of the time, but that deterrent is enough for some people to not bother including that in their search.
Still, on the whole, I've been to 5 this year, sold a bunch before and after, and I am on pace to do better with resale this season than I did last year.