This answer by u/Sid_Burn may answer your question. The OP in that thread asks your question in reverse, asking why the Holy Roman Empire was dismantled, but u/Sid_Burn definitely covered the reasons for why the Holy Roman Empire had at that time become politically obsolete.

Why was the Holy Roman Empire dismantled? Were there any people who wanted it maintained/reinstated?

This answer is, however, noticeably lacking in reference or sources and so I'm sure some others who are knowledgable in this period may be able to elaborate or provide a better answer.