288 certainly gets the most votes for the next Husky kit. And as this saw is still in production for markets outside the US, the business case for the parts makes more sense for the Farmer-Tec folks.
But while this discussion has focused on discontinued models, the AM parts support for the 385/390 and 395 is actually pretty weak. Especially the 390 chassis. Even if they can't do a complete kit, they ought to look at increasing their parts offerings for those models.
Another factor in parts consumption is a pro vs homeowner thing, because pro saws get beat and banged up every day. Parts like top and brake handles, tanks, clutch covers, starters and such are regular sellers for the pro saws. We sell a lot more "crash parts" for pro saws than for 455 Ranchers. And I get it why we're all kind of fixated on cylinder kits, cause they are cool and we can modify them and all. But parts consumption on the less exciting stuff like all of the external crash parts is big business.