I'm a little lost here. Your argument is that this is part of a grand conspiracy in academia to protect. . . big textile?

The thing about conspiracies is that there tends to be a purpose behind them. What would be the point of this one? That the cotton gin couldn't be patented? How would that possibly impact any single person today? What would be the incentive for continuing this conspiracy?

In general, historians are pretty quick to correct mistakes from their past interpretations of facts. So why would this be different?