Even the vape companies would face a bleak future because frugal vaping costs so little even a billion vapers would support a vape industry that's only a few percentage points of what tobacco is today.
I don't think nearly as many vapers would have gone down the DIY path of frugality if it weren't for the sword of regulation hanging over our heads. Think about it; you used to spend $3k a year smoking. You could have smoked RYO for a lot less. You could even have grown your own tobacco. But you didn't. Why?
I'll speculate: Because the very convenient, BT product that you were used to wasn't under threat of disappearing due to "regulations". If it were, you would have looked at rolling and possibly even growing your own. I know I would have -- at least if vaping hadn't come along.
Thus, I think if NJOY and a few others do get PMTAs approved, I believe there will be a good market for them, even if they price their products close to the cost of smoking BT cigarettes. No, it won't be those of us who've gone to rebuildable atomizers and DIY liquid. But there's still 30+ million smokers in the US alone who haven't switched, who might have a renewed interest in vaping once the FDA has "blessed" some products, especially if those companies are not part of BT.