Sorry, I meant " I don't think it would become a real problem."
However, if someone with massive hashing power could push it over the boundary, then blocks would stop, and stop forever. The next difficulty adjustment will happen after 2160 blocks are found, which will never happen.
Remember: difficulty adjustment happens every 2160 blocks, not every 2 weeks
That's true, but (Correct me if I'm wrong) it's nothing that couldn't be fixed by a fork. In fact, a fork would be even easier since the "original" branch of the network would be at a standstill. Granted, the fork would have to include some measure of preventing that same situation from happening again and that may not be feasible.