The progression in solid-state drives (SSDs) shows slow, unreliable, and "damn expensive" 30GB drives in 2005. Those drives were roughly $10/GB, but today's rack-mounted (3U) 512TB SSDs are less than $1/GB and can achieve 7GB/second performance. That suggests to him that by 2025 we will have 3U SSDs with 8EB (exabyte, 1000 petabytes) capacity at $0.1/GB.
Ignoring the limitations of physics, 8EB at $0.1/GB comes out to $858,993,459. I don't think there will ever be enough of a market to support the mass production of billion-dollar disks.