If we look back to the time this thread is created (almost 2 years) and you already invested in altcoins (the popular ones specifically) then probably you already earn huge since the prices of most coins currently are quite expensive already.

Investing in alts are more risky compared to Bitcoin but the chances to earn from it is high as well, and it depends on the coins you're going to hold. Although it takes months or years before you can see the result but atleast you made the right choice to diversify your investment and its only possible if you did an extensive research to know which alts are worthy to buy.