It becomes a financial burden on the cell phone providers to keep around a product that almost nobody wants. Because of this, they have to charge more than normal for flip phones. So, the cheapness advantage of flip phones is really deteriorating.
You used to be able to get them for free with your wireless plan. Now, they charge you hundreds for a flip phone and try to give you all kinds of deals to get a smart phone. The selections used to be bigger for flip phones in stores also. Now, it’s usually just 1 model per store, and whatever it is, it’s probably not as good as the flip phone you had back in the day.