it's a good gamble because he will probably become the best player in the world at some point. he also is brazil's number one superstar and a highly marketable personality so you can spend more on him.
Again, I don't see anything that Real did, and we haven't.
Imagine if we weren't Barca's or Real's fans, this is how it looks from the outside:
1. Barca paid way too much for Neymar
-- he has marketable value
-- plus, he can turn into a Top3 footballers one day
-- so, 100M transfer (I don't remember if his huge wages are calculated in these 100M already, but his wages were higher than Mess's, weren't they?)
2. Real paid way too much for Odegaard, but only for his WAGES
-- they didn't spend too much on a transfer fee
-- so, the only "risk" are his wages
-- since the guy currently looks like the brightest young prospect in the world, plus he looks mentally strong, intelligent and humble, it seems like it's worth a risk, isn't it?
Again, Neymar could have turned out to be a clown, and we would lose at least 50 Millions from his 100M transfer.
If Odegaard turns out to be a flop, they can still resell him for at least 5-10 Millions one day to some English club.
So, basically, they will only lose on his wages.
So:
1. on one hand, he could turn out to be a new Messi or Cristiano
-- and you only have to pay his wages to find out the answer
2. if he flops, you will only lose the money for his wages
I don't know, if we weren't Barca/Real fans, this deal looks like a reasonable risk.