Only my opinion but best player of all time is Maradona. He is the only great to have achieved his greatness without any supporting cast that could be considered "world class" or near to that level to help him carry the work load.
Whenever someone nominates a best ever player they are inextricably linked with others in their team.
Pele, Garrincha, Jairzinho, Didi, Vava, Tostao, Rivelino etc.
Cruyff, Neeskens, Haan, Krol, Rep
Beckenbauer, Muller, Hoeness, Seeler, Meier, Vogts
Di Stefano, Puskas, Kopa, Gento
Best, Law, Charlton, Stiles
Platini, Tigana, Giresse
Gullit, Van Basten, Rijkaard, Baresi, Maldini
Zidane, Desailly, Thuram, Vieira, Lizarazu, Blanc, Deschamps
Messi, Xavi, Iniesta, Puyol, Villa
and so on. Playing with players who are world class/top quality makes it far easier for you to show your qualities and to win trophies to elevate your claim to being a true great. The great players named from above are also remembered for being in great teams that define their generation. Maradona was never in a great team but his teams achieved greatness by having him in the team.
Maradona was Argentina's and Napoli's only indisputable world class player so opposition teams could concentrate on one player and in Maradona's day they attempted to kick him out the game more often than not. He still was good enough to influence his team to the biggest titles.
