I also believe that it would be good for manufacturers to back up some of their products with the research done to support why the product is good. Alas, many believe that it would give away too much to competitors. This is a very common problem with many manufacturers.
In terms of cost, I don't doubt it. However, for a beginner that wanders into the local fish store, Seachem products are usually front and center in the USA. Seachem has a strong distribution network and representatives that build relationships with big box and local stores. This comes at a cost that is passed through to the consumer.
In the past, Seachem did support my efforts at APC as a sponsor. In fact, one of the first sponsors to support online planted aquarium forums. I give them credit for that and also being willing to invest in the planted aquarium hobby.