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

fs 2 years
Canary makes very well built and good sounding gear but for some reason they don’t get much attention. 
I've owned lots of amps ss and tube. I have the Canary M350's with 300b and 6sn7 tubes. You can't go wrong with these mono blocks. Running a pair of Legacy Whispers (without the built in amps. Also ran Wilson Witt series II, and Lipinski L707''s. Cary Slp 98 Pre. Excellent sound with every combination.