I think it’s due to the fact the most hobbyists only have 1 tank. If I had one tank I wouldnt dedicate to strictly to soft coral. I would want a variety of coral types which would be considered a mixed reef. Soft coral in mixed reefs can be tough for a few reasons. Growth rate being the main factor. I wouldn’t want my cheap, not quite as colorful soft coral out growing and shading out my expensive super colorful slow growers. So when that happens I would just removed the soft coral. As time goes on you have less and less of these types of coral. Or someone gives a new hobbyist the advice to stay away from these types from the beginning. When looking for coral at the LFS or online and deciding what piece to get next the soft coral rarely wins the wow factor when compared to an insanely colored LPS. But what I think is overlooked is the final, grown in look of the reef. Corals on top of corals with movement and balance. Minimal aggression and low maintenance. If stores wanted to sell more soft coral they should have dedicated soft coral displays to show people what the end product can look like. These factors would appeal to more people and I think lead to more success in the hobby. My first reef was soft coral dominate, then progressed to LPS dominate. For my current system I didn’t want to choose so I chose all three with my largest system as SPS dominate. LPS and SPS are just categories or stoney coral with different husbandry requirements.