The mm 121 class will be with us shortly and they can hardly be classed as current IR stock (black and tan, original silver seem to be popular preorders)) also the "A" class is eagerly awaited again hardly "current" rolling stock. Just because the 201 is currently running on our rails does not mean someone will want to buy it. If they want a 141/181 they want a 141/181.
Regarding 141/181, when they were initially issued MM had the development costs to recoup. If they were reissued as is, surely having no development cost to recoup could be reflected in the price? Maybe that would allow a price point below the 121 or the "A" class. By all means keep additional unrepresented models coming but not everyone has the where withall to fulfil their needs when a model hits the shops. Me, I would like one of the small CIE shunters. It would be great for someone entering the hobby. Add in a couple of IRM wagon packs, some sidings and you are set up.
Anyway it is refreshing that we can argue over something like this. Not so many years ago there would have been nothing there to argue over!