I think that only 10% coins/tokens that would be able to survive and will be worth investing in 2021.
There are currently 2400 tokens that are known and many unknown to anyone. By the end of the year 2020, at least 100-200 new tokens will be created. Every day in the world there are 5 new airdrops. I think it is not realistic to calculate. But I'm pretty sure new tokens are being created more than they are being deleted.
But we have to buy only good market capitalization coins. Don't invest money in shit coins.
It depends on the market condition in bull run many coins are going to survive but in the market where investors are not going to try their luck in new coin they will not likely invest on it, I still see many new coins in the market and the resurgence of crowdfunding will emerge again, people are still going to look for new project that will make them an early bird.