This is often claimed by some secular and Moslem historians.
For example, in Michael Hart’s book, The 100: A Ranking of the Most Influential People in History, he ranked Jesus 3rd (After Mohamed and Sir Issac Newton) and St. Paul 6th. In his explanation of Jesus, he justified this ranking, despite the fact that there are many more Christians than Moslems, because Christians do not follow Christ’s teachings. Additionally, he claims that there would be no Church without St. Paul. Thus he demoted Christ’s influence because of St. Paul’s contribution. In his introduction, he states that he ranks individuals based on the number of lives they have touched. When I first read this book I was an atheist. Even then, I pondered his logic as it seems to have made little sense to me at the time. The logic still escapes me.