I've been a 1/6th scale collector since the mid 80's, I have several hundred figures in my collection, and I have paid attention to the trends and offerings over the years even though I collect far less than I used to. I've been involved in many of the on-line 1/6th scale communities since 1995, and TNI isn't one I count amongst them.
The stuff that Sideshow is producing, in terms of unit numbers is single-digit percentages compared to what Hasbro, Mattel, 21C, Formative and a few others were making just under a decade ago. They profit because they make enough to address a niche audience, not a mass one. The popularity you speak of is limited to those folks that wander into a specialty store (or on-line venue) to buy these, not a mass-retailer.
Yes, Hot Toys, Medicom and Sideshow have diversified, but they are not addressing a clientele that is any larger than the military figure collector base used to be--and it was discovered that collector base is a LOT smaller than people thought.
Sideshow is not selling these things in hundred units-per in collectible stores, they are selling maybe a dozen-per store. Hasbro still sold far more 1/6th Star Wars figures at TRU and Walmart but virtue of accessiblity.
I think we were going two different directions here as I wasn't even speaking of the collectibles in stores like Wal-Mart, Target,etc. That's quite obvious that there are massive sales once those items hit that market.
I was referring more to the items in terms of "collector popularity" and what I've seen throughout my experience in the field. I have seen a jump in popularity for those items that I collect and I know at its price point and target audience, they will NEVER be a Wal-Mart selling item.