You know why Pelé didn't play against europeans teams? Back then they were mostly trash, Brazilian league until the 80s used to dominate football. Santos, the team he played for, even refused to play Copa Libertadores, a tournament with the best south american teams because the level was also too low compared to the clubs in Brazil.
Why is Pelé the greatest in history? Simple, because after Pelé, football becomes professional and starts to crawl towards what it is today. Pelé forces football to change, because the way it was, it would be impossible to continue. Pelé is the breaking point between two eras, the pre- and post-Pelé eras. Before Pelé, football is archaic, with players caring little about their physical conditioning. Pelé forces all of this to evolve and seek a physical football united to the individual technical level. For many, he is the greatest genius of all time - or at least he is always in the top 3 - and not for less, he is certainly the only one who compares to Messi (or the other way around) in technical football. One of the greatest scorers and also one of the greatest assistants of all time. Anyway, it is impossible to take Pelé out of the top 3 best in history (for me, the top 2) and this obviously increases his greatness. He is the greatest player in the history of the World Cup, the only one to win 3 titles in the tournament, the player with the most G/A's, and a player with one of the greatest performances in the history of the World Cup, in 1970 (for me, the 3/4th best), all this with less than 20 games in the competition.