On average next week, the cost a ticket from Cork to Paris is €14 higher than Dublin to Paris, while Paris to Cork is €16 higher than Paris to Dublin. The differential is higher around weekends than it is mid-week.
Yields are good on that route.
There is a question of the extent to which adding capacity would undermine yields, but without trying, they won't know.
They are a business and not a charity and businesses take controlled risks. If they don't do so, they wither to nothing. What's important in business is having pre-defined rules on what constitutes a success or a failure and being willing to pull the plug on a new venture that is failing.