What's the deal with Canary and why have these amps been FS for so long?

I was the under the impression that Canary was an excellent boutique brand.
I've also been considering 300b amps for some time now. 
These Canary 300b amps seem like they aren't grossly over priced, yet they have been FS for 2 and 3 years each according to my hifishark searching. 

As I'm looking for a tube amp in this wattage range, should I be considering these?

I guess I'm just surprised they have been FS for so long.

fs 3 years
https://www.usaudiomart.com/details/649623875-canary-audio-330-mkii-300b-monoblocks/

fs 2 years
https://www.usaudiomart.com/details/649415725-canary-audio-ca300-singleended-mono-blocks/