Even if Online Mutliplayer servers go down, the Updates for games are still available aren't they?
On the PS3 you can actually update games on the XMB:
Put the Disc in or Highlight the Download on the menu, then press Triangle & on on 'Check for Update'.
Then you can Update the game from the XMB:
Might not be 100% helpful on that particular situation but it can speed up the time it takes for updates + it's a way to update a game without going through a big install.
I did have a 500GB PS3 Slm all backed up and Updated... but then even being kept in storage it somehow tanked! I've been meaning to look into another one really.
There is a legitimate reason to be concerned regarding PS3 Game Updates, I've bought all the DLC Editions I can, even the MGS4 5th Anniverasry so it had further updates on the disc. I hope in time there will be a website database where you can just download the updates from.
I'm actually now jsut putting a few PS3 games on my console now, just running the updates and not applying a mandatory install - Because when you run the game and it does an install, it can merge the update and download file together - So after I beat a game from now on I will delete the whole file, then quickly run the update search again - I know it's very OCD but these Updates are made with intention to maximise the experience.