Why can't I get a complete list of installed programs on Windows using WMI's Win32_Product class?

The Win32_Product class only returns programs installed via Microsoft Windows Installer (MSI). Programs like Google Chrome that use other installation methods (e.g., custom installers) are not listed. For a complete list, you need to enumerate the registry at `HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall`, as explained in the article Penetration Basics - Obtaining the List of Installed Programs on the Current System.