You see amazing saves fairly regularly nowadays as every match is recorded. In 1970 there were relatively very few matches seen on tv.
Also, seeing as it was on the world cup, THE biggest stage, being watched all over the world live (virtually unheard of back then), I think it's only fair it was considered "the" best ever at that time.
Nostalgia also plays it's part and Pele was considered the best player ever.
(note that this was the
first time I'd ever seen a football match in colour!)
I still think it was a special save and as was mentioned in another thread, it would be special even today.
I am therefore of the opinion that it is the best save of all time