It's using an FPGA for hardware accurate emulation which costs more than the ARM chips in retro handheld emulators, and is a bespoke fairly large product made in relatively small batches. For what if is, it's somewhat reasonably priced compared to its manufacturing costs.

I can't argue that for most people the value prospect isn't worth it, since the C64 itself isn't really a compelling platform except to specific retro PC enthusiasts, but for those who want a proper modern C64 for nostalgia sake, it's a fair deal.