Why UBP is the Original Manufacturer

Blowers are a commodity, so it doesn't matter who provides them, right?  Although a blower is a small part of the overall cost, it is actually the "heart" of the system that all other components rely on.  Without the blower, nothing operates as it should.  To avoid getting a lesser quality blower package, many engineers exclude packagers from their specifications.  Is this really the best solution?  The only remaining option becomes a factory package; however, this limits you on model selection and a standardized package without many possible modifications.