You shouldn't have been running your maintenance costs that high, I'd say.
Once your maintenance costs are within a system or two worth of your production, you need to start mothballing all of the new ships you build (reserves) and retire some old ships, or switch over to producing maintenance free units such as fighters.
If you lose a system, it would at worst cause some spaceyards to halt, rather than losing ships.
That sounds like the Beloch(Raiders of the Lost Ark) thing to say. As you can see Dr. Jones, there is nothing that you can acquire that I can not take away.