OK, I misread the OP as saying the legal problems would start after 5 years. He's still spouting nonsense though.
Even if the ZFS issue is found problematic, that won't end support. Worst case scenario I can think of is that they'll stop distributing ZFS with new downloads, or similar.
And as I pointed out, even if Canonical goes under, the product won't die.
Where does anyone get the idea that this could kill the product as it stands? That is pure fantasy.