I wanted to buy for my kids the littlebits Korg synth kit so that they can learn some basics about sound synthesis. Unfortunately the kit price put me off (here in UK the cheapest was £102). I’ve ended up buying them a Korg Volca Keys synth for only £89 delivered. The Volca Keys synth has everything your kit has plus a case, three oscillators, a much better sequencer and MIDI input (just to name a few). My suggestion is to reduce your kit price if you want it to sell.
I think the two have different purposes, and possibly different audiences. The Volca series is brilliant, to be sure, and I knew for me I wanted the modularity of the LB kit.