This story is deeper than 'life crushed this one individual's childhood dreams'.

At any turn during the story, the author could have become something much worse. He could have become a drunk, he could have become homeless. The invisible hand of the economy dangled his future in front of him as a tease and then handed him a job in the end as a threat, telling him never to be ungrateful or else.

It's a retrospective on the ways in which average people can have their lives warped by externalities. At the end the author wonders about the version of himself that became beatnik, but what about those versions of himself that became drunk and homeless? Well, those don't exist in parallel universes. They exist in this universe, as other people in the same situation as him, the same situation shared by 90% of people.