An ASN with a /32 allocation (the smallest for ISPs) is four billion /64s. It takes dozens of yottabytes of traffic to exhaustively scan one single /64. The entire v4 space takes 0.00000001 yottabytes, or about 110 GB/port in more understandable units.
There's a ton of things you can do to cut down on the scan space for v6, but it's still far huger than v4 can be.
ASN addresses are public information.
An ASN with a /32 allocation (the smallest for ISPs) is four billion /64s. It takes dozens of yottabytes of traffic to exhaustively scan one single /64. The entire v4 space takes 0.00000001 yottabytes, or about 110 GB/port in more understandable units.
There's a ton of things you can do to cut down on the scan space for v6, but it's still far huger than v4 can be.