This was also in an age where specialists didn't scale food consumption on era though. The combination of the two effects could be really upsetting, though I understand the massive upheaval certainly has roleplaying value.
If you decide to keep it at 100% degradation, 2 observations:
- The UA text could definitely be altered to better communicate the bonus going down to 0 on era. 'Degrades' doesn't imply completely lost, and is a very imprecise/misleading way of communicating what actually will happen.
- Adding an extra trigger would might be fair. Maybe add world wonder construction as a
/
trigger?