I don't get it. I work in the semiconductor industry and sell into high tech manufacturers. My company produces ultra complex products that need to be sold at amazingly low prices given the technology behind them. Same is true for my customers. Ever pop open a cell phone? Not only is this stuff amazingly difficult to develop into a reliable product, but the customers are unforgiving and the production and sales channels need to operate flawlessly.
Now consider e-liquid. Its made from readily available PG, VG, NIC and common flavoring along with a couple other ingredients that are perhaps a bit more difficult to source. While I assume there is a bit of cost in bottling, labeling, handling etc, the profit margins look pretty good. Raw cost of materials per 30 ml bottle is probably $4-6. It seems that it would be possible to keep a pipeline filled with the tough to source materials and be able to reasonably fill demand on an on-going basis.
However, I do feel a bit dismayed that some of these guys have such an opportunity to make a lot of money and get ready for when the FDA steps in. If they can't handle sourcing materials or re-building a web site in a timely manner, then they'll be crushed when faced with what is the inevitable rules, standards and regulations they'll be forced to comply with. I'd suggest to any manufacturer who has a winning formula - make a killing now and start stockpiling your cash. You'll need it, either to tool up your facilities, processing and compliance team or to just call it quits and cash out.
Of course, to be honest, part of the reason for my rant here is based on my (perhaps cry-baby & spoiled) frustration in not being able to get what I want, when I want it. Guess I'm a true red-blooded American.