I think for the longest time it was a “we don’t want aftermarket influence on our putters” similar to how Apple didn’t want third party companies making changes to their products or becoming competitors.
The Fujikura MC is a plug and play shaft for Scotty’s so we will see. I get it back today from the shop. I went with a 115g X-Stiff MC for the highest rigidity. I’ll let you all know what I think about it and if it’s worth the $250 price tag they are charging “Yikes”