Ah, finally, a direct explanation of the Horstman Curve and its MacGuire Hump. Thank you!
I think chemists will recognize the hump as "activation energy for a reaction". Which of course immediately jumps me to "so how to find/make catalysts" which will reduce the hump for one's situation? (such as bringing in an outside expert, or sending team members to conferences and trainings)
Horstman curve maps "effort for given result". Convert that as "result for given effort" and I think you get Seth Godin's "dip" which you fall into when learning something new. (Similar ideas by nicher authors earlier, such as Gerald Weinberg writing for software developers and their tech-leads [technical-track equivalent to managerial-track supervisors].)