Three other people also booked it and I didn’t get it. Qatar airways.
I flew from DFW to Sydney on a flight that was not fully booked. They made an announcement for a $150 upgrade to have an entire row to yourself. Once in the air, all of the armrests could be raised to allow you to lay flat. $150/17hours ~= $9/hour for a comfortable-ish sleep on a long haul flight. That's better math than the app subscription model threads have.
And if anyone is finding they have to help out in emergency seats on the regular, please tell us which airline.