> The world is wide open to you.

In the United States probably. The author doesn't sound too old, and says that he/she got access to the internet much later. Which means the author is probably from the Middle east or China or South Asia. The work culture there is not as open as in the west. Daily job means monotonous routine work. What excited him about the prime numbers problem was the novel aspect of it, and the fact that he was in control. Later, in his/her day job, that was no longer the case -- someone else was making the decisions. Until these nuances trickle into daily jobs, most people will sooner than later burnout.