You stated, "tsunami of ExMoose."
Allah says in His Noble Word:
O believers! Whoever among you abandons their faith, Allah will replace them with others who love Him and are loved by Him. They will be humble with the believers but firm towards the disbelievers, struggling in the Way of Allah; fearing no blame from anyone. This is the favour of Allah. He grants it to whoever He wills. And Allah is Ever-Bountiful, All-Knowing. (Surah Al Ma'idah 5:54)
You say tsunami, but statistics and demographical studies say others.
Meanwhile, religious switching – which is expected to hinder the growth of Christians by an estimated 72 million between 2015 and 2060 – is not expected to have a negative net impact on Muslim population growth. (Pew Research Center)