Remember, just because you're paranoid doesn't mean that everybody's NOT out to get you!
Like everything, there are cyclic changes to any sport. If you owned a British sports car from the 60's you couldn't go to your local auto parts store to buy a new starter for it, but there ARE specialty shops that can get one for you.
So the stuff will always be around, some of it just may be more difficult to find.
But things like covering and glue will always be available. After all, they still have to make it to build and cover ARFs so the manufacturers won't NOT sell it to you.