A lot of the technology is regulated by FDA requirements, which apply to humans but not animals. Some of these requirements are challenging engineering problems - like how to do certain type of liquid transfers without exposing the contents of a container to the atmosphere, etc. There are lots of tools for doing liquid transfers that mimic what a human would do, but FDA places a different bar when it comes to developing a controlled manufacturing process.

There's also the question of, who writes the rules. Often it's industry experts that are already working on the process, and have incentives like keeping others out or licensing their own IP.