Well, it's an internal R&D investment and it doesn't bother me as a user, because the end product is not getting e.g. any new features through this. Any new HW generation always needs some SW changes, if any software is involved at all, for any product, if it's not a knock-off...
Basically DFC is the same product as DFR, based on a newer available components. Well, at the time DFR was released, those components were also new, they also required some coding. This doesn't really justify a price increase of 50%. So, either there is some ongoing inflation in the US, which I believe to some extent is true, or AQ is just trying to milk their customer base.
I think what you're calling "milking the customer," AudioQuest would probably call "retaining sales" and "not going bankrupt."
Product pricing is a tricky business and there are books and business school classes dedicated to it. Part of the problem is that, if they had a lower price for the Cobalt, the DFC's sales will start to eat into the sales of the DFR; then they have to lower the price of the Red, then its sales will cannibalize the Black's sales. So they either raise the price of the top tier models so that it's meaningfully distinguishable from the lower models, or they risk losing sales of other models.
Then they could, say, drop the Black altogether and lower the price of the Red to fill somewhere closer to that price slot. Then what happens? Then, for new customers especially, people don't only see a $200 device that's now available for $100—a bargain— they also see a $100 device that used to sell for the absurd price of $200— a ripoff— and this image extends to the rest of the company's product portfolio. Things are further complicated by the fact that now the DFC no longer costs 50% more than the DFR, it costs 100% more.
I think part of the trick is that the price of a product isn't just a matter of adding up the costs of materials and R&D and manufacturing and whatever other overhead they have, it's all of that plus taking into consideration how that price affects how the customer perceives the
value of that product, all similar products from that company, and, ultimately, all of that company's products (and beyond that, the value of all similar products throughout the market... and when that happens it's all a race to the bottom to see who can survive the longest on the lowest margins (Hint: it's Amazon)).
Does this mean that I agree with their pricing strategy? Eh, I don't know. I'd like to think that if it were up to me, I'd introduce two new products as upgrades/updates to the Black and Red, raise the prices by something like 10%-30%, and then discontinue both of the older models... Of course, this raises the problem of having a limited product portfolio.
Like I said, it's not just a matter of adding up costs and dividing it by sales. It's tricky.