the default answer is you’re paying for fancy marketing and branding of generically-sourced stuff (Bitex or Novatec hubs etc), with appropriate levels of sneering and maybe an amusing youtube link to how to become your own wheel company.
The fact is the stuff they source is quality, the wheels are well built and come with all the spares/accessories you want, and competitive on price compared to getting those generic parts built up by your favourite artisan/mail order wheel builder. I looked at all sorts of options and suppliers for some decent alloy (non disc) wheels and they were initially bottom of my list for all the above reasons, but I ended up buying some AeroWides and am really pleased with them (I can build wheels but I didn’t have enough time to source parts and build between deciding I ‘needed’ them and the holiday they were going to be used on). I put a similar build spec together with one wheel builder, which was going to cost £350 for the bare wheels and no extras. The Hunts were £400 with Q/Rs, tubeless rim tape fitted, tubeless valves, spoke tools and 3 spare spokes.