9.99 fares are available, going much lower and how can costs be covered?
There are reasons for the demand being lower than it ought to be such as issues with connections between rail and ferry over the years (people have given up/used other means), local inavailability of through tickets and paucity of promotion/information.
At least one of the ferry companies hadn't even been informed of the deferred evening train last summer.
In fairness to IE an evening train was introduced in 2011 connecting with the night sailings along with generic marketing posters at stations.
Taking a guess Irish Ferries? If so why would they be informed when they no longer offer sea/rail from Pembroke Dock?