Also, you’re comparing 1 to 1 the total market cap of the stock market to the market cap of the crypto market.
Very few people had/have access the stock market and trade back in 1998 (I guess mainly men from 30 to 60 years old residing in big cities) while in crypto it’s mainly men from 15 to 35 years old that could be anywhere in the world. We are living different times, there’s a whole culture of people who LIVE online, this is not the year 1998, this is 2017.
China, Russia and other formerly very depressed countries are trading crypto. The stock market trading back in 1998 was reserved to a much more limited number of people.