There are limits to arbitrage. Little players can't really move prices and big players are the ones causing the effect. I don't believe the market is efficient

There are limits to arbitrage. Little players can't really move prices and big players are the ones causing the effect. I don't believe the market is efficient, especially short term. I believe that in the long term it is efficient-ish. Value strategies try to take advantage of mispricing from short term thinking but stocks can stay mispriced for a very long time.