Is it worth optimizing for future output when the life-saving metric during a global pandemic is time-to-first-dose? There are only a few factories in the world that can make something as complex as an mRNA vaccine. There is literally a shortage in glass beakers and shipping lanes are backlogged. These supply chains are very fragile and helping stabilize those would do more for vaccine supply than what's being proposed here.
The real problem limiting supply isn't the manufacturing, it's the supply chain. We now have factories optimized to produce vaccines as fast as the supply chain allows. If we start messing with the supply chains and divert inputs to factories not at the same optimization level then overall output could actually fall.