At some point the economics involves construction of a new facility, which is a pretty significant cost and, perhaps, only makes sense to a company if they expe

At some point the economics involves construction of a new facility, which is a pretty significant cost and, perhaps, only makes sense to a company if they expect there to be a persistent need for what they can produce in that facility. So, if company decision makers don't perceive that they can sell more vaccines, for a long time (many years), building a new factory will be off the table.