Recovery rate of deposit programs is generally not 100%, which leaves the shop with some surplus deposit funds that can be applied towards managing the butts.
Price that into the items. If it's not worthwhile for the store to carry them at the going price, the store is free to raise the price or drop the product. Generally the store is doing some work to sell its products in exchange for making some money. What's the problem?
That's the thing about a democracy, it's hard to screw over small vocal minorities (which the convenience stores and tobacco companies would be if you tried to screw them over). A minority (such as environmentalists who care strongly enough about this to want a law) can't just rule by decree. The environmentalists would need more resources (resources = money and people who care about the issue) on their side than the convenience stores and tobacco companies have on their side in order to get a law like that passed and in practical terms that usually means getting the apathetic majority to not be apathetic the issue at hand. I see that as being very much an uphill battle in this case since the law is against the self-interest of every smoker who would have to bear the cost at point of sale.
Pursuing biodegradable (in a non-geological timescale) filters is probably a better all around option anyway since even with a deposit not all soda cans make it back, compliance for something like cigarette butts would be far less because of the issues outlined in the article.
I don't think anybody suggested that we should subvert democracy in favor of ruling by decree. I also don't think that the numbers of people and amounts of money on each side of an issue are immutable or are unassailable barriers to progress toward the minority side of the issue.
I can get behind your second paragraph (though it wasn't there originally, which is probably why you got flagged).
Nowhere in the comment you replied to was it suggested that it would be achieved by undemocratic means. Ironically, in your comment you imply that democracy consists of lawmaking by whoever has more money.