While you're correct that the price-point of DynaGro's bases are usually in the $50 range, their formulas are very concentrated which means you'd use less to get to your desired EC. That is where you save money, their bottles will last you a very long time.
In regards to Botanicare's Pure Blend which I used for 9 years, 1ml of their grow formula adds 84ppm to a gallon of water. DynaGro's grow formula adds 130ppm meaning that DG grow is 54% more concentrated. Botanicare's PureBlend is not 100% organic and when it comes to taste, I could never tell a difference after I made the switch to DG. I did get better yields with DG and it was less salty and easier to use than the PureBlend line. PureBlend is also one of the least complete fertilizers on the market supplying only 5 of the 16 essential elements. That tells me it's intended for soil which is hopefully supplying the 11 other missing elements; more added cost.
There was a study I read about while doing research on Warren Buffett where it showed that people, regardless of actual proven quality of a product, would tend to actually buy a pricier product over similar products that were on a lower shelf with a lower price
IOW regardless of the fact that DG will give solid results, the average consumers will opt for a pricier shinier product like AN or GH and assume that because it costs more, it must be a superior product. (To be fair I dell to this myself as my first nute line up was first Fox Farms big grow for veg followed by Advanced Nutrients sensi bloom A&B, big bud, bud candy, rhino skin, overdrive, and finally Final Phase for bloom... cost me a left nut for all of that shit.....)
Now that I know better I look at the make up of nutrients and though I'm have very little experience and knowledge of nutrients for plants in general, I feel I can make way better decisions as to what to use my hard earned money on.
With thay said, I've noticed that as far as I can tell, The ever unpopular Miracle Gro is very similar to Dyna Gro as far as ratio and containing micro nutes...
So I conclude with the question, why all the hate for miracle gro????