[Suicide Junkie]

Yes and no.
If the pirate race never left the nebula, then it would quickly succumb to the ravages of maintenance with no income. You might be left with one or two vehicles by using your $1000 minimum income, but you would certainly be in no position to consider that anything other than a loss for you.

The same sort of thing occurs when a normal empire is left with only minefields, and are not completely destroyed.

Feel free to use the nebulae as a secure base of operations, but don't bother being a hermit, since the game will be quite boring if you do.