What exactly do you mean when you ask "Why was the Holy Roman Empire not re-established?". The lack of specification in your question makes it difficult for me to give an in-depth answer. But I'll interpret your question as "Why wasn't the specific institution: The Holy Roman Empire in its pre-abolition reality, re-established by Austria during the congress of Vienna?"

Why on earth would Austria revive the HRE? By 1815, there was no valid justification for the HRE's existence. You've likely heard of Voltaire's quip that the HRE "is neither holy, nor roman, nor an empire" but that barely scratches the surface of how inept it truly was. By the time of the french revolution, there wasn't even a general consensus on what the HRE even was. Was it a union, an alliance, an economic pact, or something else? Well, it was effectively nothing. Members of the HRE had completely independent governance, diplomacy, and military from their overlords. Members and non-members were virtually no different.

So perhaps it's unsurprising that the HRE collapsed as soon as even a little pressure was applied. Note my use of the word "collapsed" not "dissolved". When Napoleon marched into the heart of German territory the HRE failed to even unite on a single decision much less repulse the foreign invader, this is when the institution of the HRE virtually became non-existent. It was at this point that the HRE was dissolved by the emperor. The fact that it was officially dissolved hints that Austria saw no reason to ever revive the HRE ever.

Although that's the reason "Why wasn't the specific institution: The Holy Roman Empire in its pre-abolition reality, re-established by Austria during the congress of Vienna?", this explanation leaves a lot of crucial details out. For example, although Austria was disinterested in reviving the HRE specifically, that did not mean that Austria was disinterested in the influence it had in the HRE. In the congress of Vienna, Metternich (The Austrian Prime Minister at the time) created the "German Confederation". the GC was everything that the HRE was speculated to have been: a union, a military alliance, and an economic pact. Although officially and literally the HRE was never revived, in the spirit it certainly was.

Hey there,

Just to let you know, your question is fine, and we're letting it stand. However, you should be aware that questions framed as 'Why didn't X do Y' relatively often don't get an answer that meets our standards (in our experience as moderators). There are a few reasons for this. Firstly, it often can be difficult to prove the counterfactual: historians know much more about what happened than what might have happened. Secondly, 'why didn't X do Y' questions are sometimes phrased in an ahistorical way. It's worth remembering that people in the past couldn't see into the future, and they generally didn't have all the information we now have about their situations; things that look obvious now didn't necessarily look that way at the time.

If you end up not getting a response after a day or two, consider asking a new question focusing instead on why what happened did happen (rather than why what didn't happen didn't happen) - this kind of question is more likely to get a response in our experience. Hope this helps!