Have you thought of turning your wrappers into a service/SaaS offering? Sounds valuable!!
This seems like one of those complex-enough areas that having multiple groups and companies contribute to a common good could really pay off for everyone.
But to your points: because there is no good open source initiative that does what PDFJS Express does, commercial providers like PDFJS Express and PSPDFKit are able to build pricy SaaS offerings.