Bangoman
True enough. Perhaps from an initial sales perspective, the OTS SL may fly. Like you say, people will buy anything and spend money needlessly on the latest and greatest, grabbing hold of the latest fad. And then when they find that they didn't haven't arrived in golfing Valhalla, they will move onto the next thing. If that's what the industry is about (and it is to an unfortunate extent), then the OTS SL may be a "success."
The problem with this scenario is that the success is short-lived, and the OTS SL irons will go the way of the Tommy Armour EQL. Then the masses chime in, saying, "See, the concept doesn't work." From that perspective, not only are the OTS versions a failure, but they doom the concept.
I think for people to really see the benefits of SL irons, they should be fit. A length and lie fitting is the bare minimum. That's probably true of all irons, but in the case of SL irons, if they aren't at least minimally fit, you end up with eight clubs that you struggle with. At least in a variable length set of irons you're bound to find a couple of irons that suit you to some degree.
Happy New Years and all the best with your new venture.