The whole thing is stupid, and the idea that people are just going to want to see merch of only Shatner, Nimoy, Nichols, and Doohan is going to bite them in the ass, as somebody said here a while ago. As well, the audience for merch of the old series is shrinking, with the last generation being Generation X; when they die off, what then? They have to start making prose novels and other merch based on the current continuity.
I think you're misunderstanding the situation (assuming that this claim's correct). It wasn't that CBS wanted to stay just with the old cast and refused to merchandise the new. It's that Bad Robot refused to allow licensing unless CBS abandoned merchandising the original cast entirely. CBS would've been happy doing both, but Bad Robot forced their hand and made them choose between either having merchandise of the original cast or having merchandise of the new cast.
Unless you're saying that CBS should have agreed to stop printing or publishing anything related to the prime universe and should've just let the Abramsverse replace it all?