Not sure about the natural rubber ones, but the silicone ones can be boil-sterilized. But again, then you run into the taboo. If you can't afford sanitary napkins, can you afford a pot specifically for boiling your cup? Would you even be able to get past the taboo to boil it in the same kitchen that you prepare food in, even if it did have its own dedicated pan that never touched food?

Edit: Oh, and as jackityquack mentioned in the sibling comment to this one, that requires running water. I didn't even think it that far, but yeah...that's an even bigger barrier.

Like without running water.

And, yes it might be the most cost effective, but if you can't convince a white person to use it, then we shouldn't be telling Indians to use it either. It's an option, but the market should and will decide. (p.s. my roommate uses one too.)