Equilibrium is the state in which market supply and demand balance each other, and as a result, prices becomes stable.
Some people argue that it's impossible to outperform the market because everything is already priced in so there are no good deals to make. They call it "The efficient market hypothesis".
This is one of the craziest things i have ever heard in my life. Let me tell you why:
First you have to understand, what exactly is a financial market? It's a place that exists of market participants and together they form a consensus (of price). All market participants have to make decisions with a limited amount of time, limited knowledge and resources. There is no such thing as perfect knowledge. Then how can the market have things 100% right? It doesn't... Let's take cryptocurrency for example. What is it really worth? There are no earnings and valuations like you have with stocks. How are you going to value cryptocurrencies 100% accurately? There is always a degree of speculation baked into the prices.
Boom and bust are another good example why this hypothesis is BS. What exactly is rational about that? It proves that people are driven by greed and fear. That's why financial markets go through cycles and waves. History always repeats in some way because people react on the same type of way to events. Because we have the same type of motives. Most people want: power(/fame), money and love.
Some investors have been outperforming the market consistently. But it's kind of a pareto principe. 20% of traders make 80% of the money. This is true with most things in business.
Something i learned from George Soros <3 , in my opinion one of the greatest financial philosophers all time. Markets are reflexive because what we think has an influence on reality and reality has also an influence on what we think. So causing feedback loops between them. What we think as investors is very important because investors don't base their decisions on reality but their perceptions of reality. Some security is worth a certain price because market participants thinks so.
George Soros his book "The Alchemy of finance": https://amzn.to/2EzzUhN