I don't believe that we "should focus all of our resources" on FAI, as there are many other worthy activities to focus on. The argument is that this particular problem gets disproportionally little attention, and while with other risks we can in principle luck out even if they get no attention, it isn't so for AI. Failing to take FAI seriously is fatal, failing to take nanotech seriously isn't necessarily fatal.

Thus, although strictly speaking I agree with your implication, I don't see its condition plausible, and so implication as whole relevant.