[lizardactivist]

It's because the search space (number of possible keys to guess) is astronomic; 2^256.

If you had a billion people, each person owning one billion computers, each computer capable of guessing a billion keys per second, then a billion years would still not have exhausted one-billionth of all the possible keys.

[nashashmi]

That makes sense. So his wallet will be broken in about 10 years plus 10 years marking the time for advancement of CPU and time for brute force to spend calculating with the advanced CPU.