A similar phenomenon occurred recently, when the Bank of India (RBI) announced in November 2016 that the counterfeit 500 and 1,000 ruble banknotes were no longer valid due to their proliferation and increase. Although these banknotes can no longer be used as a common currency in India, their value is still preserved as a work of art or souvenir.
What is your opinion about the proposed scenarios? Is it possible for Bitcoin to fall to zero or be replaced by another Cryptocurrency?
What you referred as a similar phenomenon is completely irrealivent to the BTC. BTC is a decentralized currency where as the INR( Indian Rupees) is centralized currency controlled by RBI itself, so RBI has the power to take any decision over it's own cerculated money. In case of BTC there is no authority on the top who can control it.
P.S- RBI gave 3-4 months time to change the old 500 and 1000 Rupees banknote into new one.