I think its about someone's desire to leave the modern world and live a simpler life and commune with nature, etc. but he can't because of responsibilities, etc. The "man ... grows old every day" is the singer - trapped by the restrictions society has put on him. He'd rather be a hammer (a doer who has control over his actions/destiny) and not the nail (and feeling powerless by others). He'd rather be a sparrow (free as a bird) and not a snail (crawling and eking out a survival). The swan is the perfect symbol of nature. He is striving to be that.
I think its about someone's desire to leave the modern world and live a simpler life and commune with nature, etc. but he can't because of responsibilities, etc. The "man ... grows old every day" is the singer - trapped by the restrictions society has put on him. He'd rather be a hammer (a doer who has control over his actions/destiny) and not the nail (and feeling powerless by others). He'd rather be a sparrow (free as a bird) and not a snail (crawling and eking out a survival). The swan is the perfect symbol of nature. He is striving to be that.