The technician failed to properly diagnose the issue by not establishing a theory of probable cause. Instead of investigating why the network drives were accessible wirelessly but not when docked, the technician assumed a faulty network card and ordered a new laptop. Proper troubleshooting involves developing a theory of what might be causing the problem, based on the symptoms and available information, and then testing that theory.
In this case, the issue could have been related to docking station settings, network configurations, or hardware issues specific to the docking connection.
References: This answer is grounded in standard troubleshooting methodologies, which emphasize the importance of logically deducing the most likely cause of a problem before proceeding with more drastic measures such as replacing hardware.