I think 90% of tokens / coins will survive 2021; i see 2021 as a repeat of 2017 where there was bitcoin price success and there were introduction of several tokens, projects, product; and then the altcoins bull season. If you noticed since last week; binance smart chain tokens are experiencing all time highs; price growths etc. There will be more tokens surviving 2021
90% will survive 2021 is too much, there are many coins with no current trading volume. 50% are more realistic and about 20% are investable coins.