He doesn't have any point. You are just trying to make one out of what he said base on "if he was here now instead of this and that he would score 50ish goals", which is pure assumption. His logic is flawed and expressed in a quite childish way.
"The quality was much better before. You see how football is not good when [Lionel] Messi and Cristiano Ronaldo, the best today, are scoring 50 goals in the championship. This shows that the level [of football] is lower. Even for the best in the world, you should not being scored 50 goals in 38 games."
What kind of logic is this exactly? He's basically saying "if you are too good it just means that your opponent is bad". Nonsense.
Football is football, I don't agree with him that football was better in 70s, 90s or today.
There is always a similar amount of good players around, more or less.
Every era has it's own heroes.
I am saying that the number of good players is the same, but the balance is different.
Good players in the past played in 20-30 different teams.
Today all good players play in 4-5 superclubs, and these, extremely rich and successful superclubs are then trashing all of the opponents by a much lerger margin than in the past (6:0 and 8:0 instead of 3:1), and thus a personal stats of players playing for Barca today can be (in fact, are) much higher than in the past. So, some current players make look like superheroes, even though they are just "normal" world-class players like guys from 70s or 90s.
It is ok when Messi bangs 50 goals, but when 2-3-4 different players bang that many goals, it is clear that the balance between teams have changed.
I assumed that Rivaldo wanted to say something like that, but he said it in a wrong way.
Plus, that part about how he would be the best player in the world was too egoistic and not needed.