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Is there an example of a library being sellable, so that it can make enough profit to become what you’re talking about? It seems to me that frameworks + GUI wrappers are more marketable so that’s what every long-lived popular solution is.
Not in recent history AFAIK, but I’ll throw two years of my life at the wall in an attempt to make it stick.
You can if you find the right need to address, like @sehurlburt and her team have accomplished.
If anyone wants to take a crack at the business side of it (specifically business, not the technical details) I always love strategizing about that and helping more small companies take off 
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