I can tell you it isn’t costs. They don’t drill the touch hole because India has strict gun control and it is a legal thing. I have talked to a couple of their big wigs. Is a serious law which is what they told me.They don't add the touch hole to keep costs down. My understanding is that India taxes real firearms, including black powder muzzleloaders, heavily. There are also additional costs incurred in export/import fees.
If they don't drill the touch hole it is non-functional - a wall hanger for decoration.