How and when will the Whatsapp monopoly be broken

WhatsApp is basically a monopoly in many countries. In these countries, it is difficult not to use WhatsApp. Every now and then, there is a big privacy scandal which increases the downloads of competitors, but at the end of the day, people keep returning to WhatsApp. Nothing lasts forever, including monopolies. So the question is, when will the monopoly be broken and how? Is it government regulation? Some countries might want to make interconnectivity of messaging apps required by law. Or is it something else?