Retail investors are usually non-professional investors and on long term they are the losers of the market. They buy when professionals sell and sell when professionals buy. They are the ones who follow the masses and invest based on emotions. They used to enter the market when it is already too late. When a lot of retail investors want to buy cryptocurrencies, it is a sign that the bull market is ending soon. That is when professionals sell. Google search statistics is a good indicator to see their interest in crypto investing. I recommend to use a timeframe of 5 years which usually includes a bull market and bear market too.