So Ben Franklin in the 20th century being genetically "one of us" would adapt quickly and in time fully assimilate while a 20th/early 21st century person could find themselves woefully inferior in mental/physical powers as compared to the late 21st century person and experience culture shock that never wore off.
Of course, I realize some readers may say that he can be genetically engineered to be the equal of the societal mainstream. But this may not be possible for an adult or may be too expensive. Any thoughts? Perhaps they would just have to wait until technology advanced and they could be "upgraded" but then they would probably always be several rungs behind on the ladder.
best regards,
John Grigg