Scale of economy is exactly why I don't do 60% specific. It's much easier to target fullsize with only single package option, and get maximum buyer that is need to even reach a MOQ or lower price tiers. If only offer ANSI 60%, it would automatically leave out many potentially interested participant. If it even got enough interest to go to production at all, it could easily end up more expensive that a full set may have been with more buyer.
I would much rather just do set that works for majority of keyboard. It makes it easier for buyers as they can see it will work with almost anything current and future. It make it easier for 'seller' only have to package set in one single configuration, leads to much quicker packing and delivery with less error.