Este é um post antigo, mas estou colocando a resposta aqui para futuros pesquisadores.
O recurso --convert-links
acontece somente após o download do site ser concluído. Eu acho que, com um site tão grande, você tentou parar o processo depois que algumas páginas foram concluídas e, portanto, o processo ainda não havia sido iniciado.
Veja também link
A partir dos documentos do wget
‘-k’
‘--convert-links’
After the download is complete, convert the links in the document to make them suitable for local viewing. This affects not only the visible hyperlinks, but any part of the document that links to external content, such as embedded images, links to style sheets, hyperlinks to non-html content, etc.
Each link will be changed in one of the two ways:
The links to files that have been downloaded by Wget will be changed to refer to the file they point to as a relative link.
Example: if the downloaded file /foo/doc.html links to /bar/img.gif, also downloaded, then the link in doc.html will be modified to point to ‘../bar/img.gif’. This kind of transformation works reliably for arbitrary combinations of directories.
The links to files that have not been downloaded by Wget will be changed to include host name and absolute path of the location they point to.
Example: if the downloaded file /foo/doc.html links to /bar/img.gif (or to ../bar/img.gif), then the link in doc.html will be modified to point to http://hostname/bar/img.gif.
Because of this, local browsing works reliably: if a linked file was downloaded, the link will refer to its local name; if it was not downloaded, the link will refer to its full Internet address rather than presenting a broken link. The fact that the former links are converted to relative links ensures that you can move the downloaded hierarchy to another directory.
Note that only at the end of the download can Wget know which links have been downloaded. Because of that, the work done by ‘-k’ will be performed at the end of all the downloads.