People aren't buying them at the value you think they're worth because they're dated and people can find better for the same money..
You've gotta sell technology stuff FAST and keep a low inventory.. Any fast improving technology is like playing a game of hot potato trying to sell. You get it? YOU SELL IT!!!!
Also, you only listed red and blue models, which nobody seems to use anymore. And did you try 730nm pulses at lights out? Have you considered that you and your hydro shop staff lack the knowledge to grow with leds?
I've been watching these led grows since people were using red street lights with epoxy lenses and have been watching the steady progression. LEDs are eclipsing HPS right now.