Do you want to build a kit, solder and supply/build the box and consider that for $0 (like your time is worth nothing). If you enjoy DIY, that’s one thing, but this obviously isn’t apples to apples.
I like DIY but to build a nice box, and make enough profit to resell and support the product, this might end up more like $1000+ (for a small 5.25” bookshelf).
There are plenty of other designs on the market using the very good sb acoustics and scan speak drivers but we are pursuing a line of planar magnet hybrid speakers which have certain technical benefits (wide dispersion, low distortion, rather high dynamic range , and low stored energy). Yes there are other designs which have smoother FR and in-room response.
However, the design target is still an even tonal balance and extended bass on all PS speakers so far.