I've been trying really hard not to get involved in these threads for obvious reasons, but I can't resist...
Firstly, talks of 'millions of litres' are just absurd. I know I speak for pretty much all the vendors that take the time on here to answer questions and get involved with the community that we are producing artesian products in small(ish) batches that are nowhere near these volumes.
Secondly, as others have pointed out already, it's easy to see why somebody who is used to DIYing their own juices may feel that we who produce commercially are 'ripping people off' or charging unfairly, as the base materials can be fairly inexpensive.
Unfortunately, the costs of raw materials only accounts for a small percentage of the overheads for any manufacturing operation, e-liquids included. I have noticed that this is often overlooked - probably because those who DIY know that it is a relatively simple process to mix an e-liquid. This arguement does not represent the true cost of the final products after all other factors have been considered.
Like any industry, there is a wide range of products available to vapers, and a wide range of options for people to make their own juices. Nobody is stopping them, in the same way that nobody is stopping anybody from cooking their own meals, cutting their own hair, making their own clothes, brewing their own beer etc.
If people like and wish to buy our products, they will. If they deem it too expensive or substandard, they won't. I do know, however, that the prices we charge are fair, and the mark-up is nowhere near what a lot of people would apparently expect.
All I can say is, if there really is ridiculous mark-ups to me made and an easy fortune to be had in this business, I for one am doing something seriously wrong and would love some pointers from some of the apparent experts on here please