That seems a bit alarmist, to me. Your math confirmed mine, one week minimum to reach level 14. It's a 2 week event, twice as much time as the minimum. People CAN sleep and still hit L14, they can almost sleep for 12 hours a day and still get the last thread before the event ends.
Minor point of disagreement: I don't see how it matters what day or event level you're at when you spend gems on energy, 1 gem always buys 1 energy. You don't get a better rate for waiting.
If there was a fixed price to fill the battery I would agree with you.