Yet, you're unable to even start because the comparison is very apt.
You've only followed Federer. You did not follow Connors throughout his entire career. Thus, you can't even start to compare the two.
For example, after their respective last US Open titles, both continued to consistently make the semis and quarters. Connors made the semis in '84, '85, '87, and quarters in '88, '89. Federer made the semis in '10, '11, '14, and the quarters in '12. Thus, Connors making the semis of the US Open in '91 is nothing out of the ordinary, as it would be for Federer in 2015. Heck, Connors made at least the semis of the US Open 14 times in his career (including 12 times in a row!). Would Nadal get a flood of new endorsement deals if he makes another semi of the French Open in 2016?
BTW, Connors won 110 singles titles during his career (the last in 1989 and NONE after that ONE match in 1991). Not even Federer will come anywhere close to that. Let's see if you can "fathom" that.