I hope this was not discussed before, this will be a little write-up on how Hiro and Zero Two might have accomplished less than you would hope. Spoilers lie ahead so if you didn't finish the Anime yet proceed at you own risk.

To start I'll tell you a bit about how you can put civilizations into "Types" why is this relevant? Just bear with me for a bit and you will see. The most commonly used system for tiering a civilization is the Kardashev scale.

It rates civilizations by their energy consumption, though there have been other systems proposed this one is still the most commonly used.

The important takeaway from the Wikipedia article is:

• A Type I civilization--also called a planetary civilization--can use and store all of the energy which reaches its planet from its parent star.

• A Type II civilization--also called a stellar civilization--can harness the total energy of its planet's parent star.

• A Type III civilization--also called a galactic civilization--can control energy on the scale of its entire host galaxy.

Why do we use the energy consumption to rate civilizations? The more energy that is available to a species allows it to make greater scientific advancements. An example would be the dyson sphere, we have a concept already cooked up for one but we can't build it yet due to a lack of energy available to us.

Where do the VIRM come into play here? When I watched the last episode I noticed just how freaking advanced they were, just the fact that they have completely transcended their bodies should be a dead giveaway of that fact.

On top of that they seem to be able to easily travel to foreign solar systems and possibly even galaxies (this mostly depends on how far the warp gate from episode 23 took hiro and zero two).

We can also see several different types of ships in the space battles which leads me to believe that they have taken over several civilizations.

With all the technologies we see them using it is pretty save to assume that they are firmly a type 2 civilization and maybe even a type 3.

Why does all of this matter? Any civilization that has advanced to space of interstellar/intergalactical travel will for sure have set up bases outside of it's home planet, so while losing it would sting for a few reasons it should not be a huge loss for the species as a whole.

So all in all I would say that Hiro and Zero Twos sacrifice set the VIRM back quite a bit, after all they likely lost a good chunk of their fleet and an entire planet but depending on how close they are to Type 3 status they might be able to recover really quick.

Who knows maybe they were already on their way back to Earth by the time Hiro and Zero Two met the second time.

Now this theory has one huge flaw, it assumes real world logic applies to a fantasy universe which is always bound to fail. None the less I still liked doing this as a little brain exercise.

If you wonder where humanity places on this scale, we are currently somewhere between 0.7 and 0.75

That is all for now, I hope it was an entertaining read and I would love to discuss this some more with you guys so feel free to comment away with your thoughts and ideas on this matter.

TL,DR:VIRM is too advanced to care about losing their home planet and may already be on their way back to earth by the time Hiro and Zero Two met again.