As compared to cryptocurrency market, the prices of stocks in stock market are quite stable. Unlike various altcoins, they do not suddenly increase or decrease (pump or dump) with 30-40% in a day.
There are thousands of altcoins, many of which does not have an actual working or practical product, and hence nothing to support the price from falling or to dictate how high it rises.
Bitcoin is also volatile, not as much as majority of altcoins.
Mass adoption is one of those factors that would bring aboit price stability. And pairing the price with products and services not fiat.