That Federer won 11 in 2004-07 is just product of his era. Just like Djokovic won 12 in 18-23.
But Federer won total of 15 Mickie mouse tournaments in these 4 years. Let's never forget that. Not slams/Masters/ATP finals.
But random 250s and 500s where he was getting huge appearance fees.
Djokovic won 8 MM in 6 years. Keep in mind. Difference is drastic.
Keep in mind that Federer's glory years were in '04-07, when his rivals, Nadal & Djokovic, were still teenagers. Federer's years of '08-retirement were less than satisfactory, with him winning one post-'11 slam with a healthy Djokovic!
Djokovic's glory years were in '11-18, when all of Djokovic were in their primes, and Djokovic had proven he was the best! Djokovic's '19-23 were in insignificant, because he had proven himself!