A skillful warrior can achieve his own invulnerability, but he can never bring about the enemy’s vulnerability. (Sun Tzu) This campaign exposed numerous operational, tactical and strategic mistakes that the Athenians made; which ultimately lead to them losing this war. One of the main reasons the Athenians failed, was because they did not have the right resources nor executed the right strategy; this was mainly due to lack of planning and a lack of willingness to adjust. Maybe if they had planned accordingly to their strengths.
Another reason was because of the recall of Alcibiades. This de-motivated the troops due to the fact that he was such an aggressive and arrogant person, and they believed in him and wanted to follow