In fairness, we have never said we would not be releasing ploughs, ballasts, etc. with CIÉ markings and I think it’s a little unfair to say there’s an IR/IÉ slant in what we’ve produced to date when most of what we’ve turned out so far (i.e. ivory and orange cement bubbles) carries a big fat CIÉ logo on the side.
However, there are several factors we have to consider when we decide what to produce and ultimately the head has to overrule the heart when making these choices.
One factor is the suitable RTR motive power customers have to hand: the majority produced is appropriate for the IR/IÉ eras, so while CIÉ may do well in surveys, if customers want to simply buy rolling stock to run with their locos then it should match what they have. That doesn’t mean we won’t produce the products with CIÉ markings, it just means it won’t be the first lot off the production line. (Similarly, while some customers are shouting out for Midland six-wheelers, it doesn’t make sense for us to produce one when there’s no RTR loco out there to haul it - and the reality is that most people aren’t going to build a suitable steam loco kit). If more locos appear in CIÉ colours, that'll help change our thinking...
Another factor concerns ‘product fatigue’ and diversification of what we offer. We could have done all variations of the ballast wagons from the outset, but that would’ve required a greater outlay while also putting all our eggs in one basket. It took a year for the ballasts to sell out – anyone sticking to a single product and waiting that length of time to exhaust supply before moving on will find themselves in a tight spot very quickly. The upshot is that we still have the tooling, so we’re free to revisit these items in alternative liveries once the range is diverse enough to prevent people getting bored of seeing the same one or two items over and over. It makes sense for us to maximise use of all our moulds (which, incidentally is another reason why we chose the current weedsprayer and not the older version, in answer to Iarnrod's comment above).
That's just some of the reasoning behind it. There's more, too, but you get the idea...