The answer is the first one.
In "Writers often disavow the notion of a 'literary duty'" the author conveys a somewhat condescending attitude, as if they would always follow this and set aside anyone who said otherwise. This attitude says the author is looking down on them, and that the author believes that many authors do not meet their standards.
Another answer I would consider is "...writers ruined by their shrill commitments." However, there is no context or clear tone. The author could be mournful of the lost potential for all we know.
Answer:
The symbol of commuters as birds illustrates how they come and go without ever experiencing the city.
Explanation:
They go from city to suburb, from the air to it's roost, one could say, but never get to experience what the city has to offer. They don't have the freedom to come and go, because they go there to work. Meaning, having to fulfill some economic needs, responsabilities, etc. They don't go because they feel like going.
They do offer something positive though because, again, they go there to work. A city -a society- needs its body of workers. It needs people to work, doesen't matter if it's from a suburb or not.
The symbolism of the suburbs as a "roost" expresses the safety and comfort of the commuter’s home is wrong because he says:
"The suburb he inhabits has no essential vitality of its own". It is pictured as something sad, empty.
