I posted about this not long ago. Prices per ml that are 2500% higher than the price of 10 year old Bourbon that is paying regulatory taxes no less.
So YES they are bending people over. BUT, they couldn't do that unless people willing bent over to take it. Free Enterprise dictates a demand economy for good or bad. It the market will give $1 per ml of juice then so be it. I personally won't be doing so anymore but on rarest of occasions and it had better be good. I've tried so many "Premium" flavors in shops and they are all just blah to me for the most part.
If everyone would take the plunge into DIY and use the forums to pass on their creations we could all find what we wanted or close to it for our tastes for pennies. These juice companies are making a killing right now. Just think when government starts to regulate and tax them how much more a bottle will cost? All the more reason to get into DIY and learn. I just did and I am more than happy and we have a great start right here on ECF to learn from each other and make our own juices we like. You can look at profiles of flavors you might like from recipes and then adjust the % or add another flavor, leave one out etc and get creative.
These companies (well some of them) I am sure put lots of time into testing mixes to get a taste profile they want. But in the end they are just guessing and I am willing to bet making a large spread of flavor %'s at once to reduce time to find the right mixes. Even in my little clandestine juice lab

I realize I am just chucking flavors I think will meld into what I might like on a whim. So I do 3 or so small 3ml batches with varied %'s and test. Gets me closest quickest.
These big juice makers are buying their supplies in bulk (I hope) so their cost is minimal. The bottle and label probably exceeds the cost of the juice itself especially once you include labor and any overhead.
I'm off to vape on my Sugar Bear Cuttwood clone I discovered on here and tweaked to my taste. So long $25 per 30ml B&M store pricing. Costs me about $1.20 now!
Having working in Industrial Chemicals I know how cheaply you can get 55 gallon drums of things for and the markup by the time the maker sells it and the retailer marks it up on the end is likely in the 1500% to 2500% range. Not bad margins if you can get people to pay them!
CC