Again, it was only cost-effective to build farming rigs in the very beginning. It is no longer cost-effective to do so. Even major companies will eventually have a tough time competing with the amount of storage space that is already deployed in the world. IIRC is around ~7 Zettabytes. That is the big difference with Bitcoin. Chia is making use of a resource that already exists in the world and is well distributed. Bitcoin ASICs require manufacturing and building machines for the specific purpose of mining Bitcoin and then distributing those machines.