There are product cycles for nearly everything, cars, cameras, stereos, and kendama. New colorways are a different but related topic but how often do you think the companies should be changing their ken design/shapes? How often have you found your perfect kendama and then had be it discontinued?
This is a tough one to answer in brief. Companies really should be mindful of changes in the mainstream shapes, but at the same I hate seeing good shapes get retired early. A good example is the Sol shape. It kinda reminds me of DWI, but now they are just pushing 1Up shape, which is a fantastic shape. I miss the Sol shape too. I’m also aware of the OG Tk-16 crowd, and that’s a respectable yet extreme scenario, kind of like people that only ride fixed gear bicycles. Then there’s companies like Quill who change the shape multiple times a year never to remake them again. This ups collectability but downs long term consistency. Fortunately there’s a place for everyone in this awesome community.