I'm not sure where you got your stats there, but after looking it up myself, Harbaugh was 8-11 going into this season against top 25 which would make him now 9-12. Franklin is currently 5-11. Both are bad. But Franklin is nowhere near as bad as you say. Overall Jim Harbaugh is 43-15 at michigan for a .741 win% and James Franklin is 51-21 at Penn State for a .708 win% and one B1G title.
Penn State had the #2 class in the B1G in 2015 and 2018 while michigan was 5th and 3rd respective. Michigan had it in 2016 and 2017 while Penn State was 4th and 3rd respectively, so they are pretty close there.
Harbaugh is 1-3 in Bowls, Franklin is 2-3.
NFL wins are totally irrelevant because its not college wins. Are you sure you aren't a michigan fan? They love that particular straw man.
So once again, the two coaches are very similar and I'm just not seeing anything that would suggest Harbaugh is better than Franklin, let alone by a significant margin.