My understanding is Husqvarna implemented one of the Japanese parts delivery systems like
Kanban (similar to Just-In-Time) at the same time much of the previous U.S. manufacturing was shifted to China, with the two systems being incompatible. Basically you order the part which gets subtracted from inventory and the computer system adds it to the next the Chinese factory run for those parts, the problem being distributor inventories were depleted during COVID so there was no existing stock to act as a buffer. Distributors are concerned the increased issue rate with the most recent saws coupled with higher saw and parts prices will negatively impact demand for OEM saws and parts driving people into buying aftermarket parts and saws and therefore "not necessarily restocking parts inventories to previous levels."
(I think that means "not restocking.")
Aftermarket Example: Holzfforma/Farmertec = Jinhua Farmertec Import&Export Co. Ltd, 2500, Liyu Road, Jinhua City, Zhejiang, China
I'm hearing Husqvarna is trying to adjust the computer variables to add parts to the distribution pipeline therefore shortening delays but it's tricky because they could wind up with parts on the dock but no orders to fill, therefore creating excess inventory and no place to warehouse it.
STIHL shut down at least two U.S. plants due to decreased demand after COVID (actually a near complete stall in demand) amidst a global worker shortage, leading to an unsolvable supply shortage. STIHL has chosen to focus on new saw demand figuring current owners will either wait on parts or buy a new saw, whereas saw unavailability might shift current customers to another manufacturer. So STIHL customers are facing a similar problem as Husqvarna owners for a different reason.
Echo is doing great though, prices of saws and parts are just above cost and Echo is gaining market share. Echo has a great parts program and if we know anything from car manufacturers it's: the money is in after-sale parts purchases (in this case chains, oil, bars, repair parts). Adding icing to the cake, whereas STIHL and Husqvarna have new product development costs, Echo is using twenty-year-old proven technology and doesn't have that overhead to pay for.