I think because this is a small batch run of watches for those who are fans of Pebble. Think of it almost like we would say an FPGA device for playing retro games, or a retro upscaler. They're usually prices quite high because they're niche items with small production runs.

These watches are for people who were fans of the original Pebble and miss it, therefore they're willing to pay a bit more to get back something that they thought they'd lost.