The number of traders is increasing more than before as more people are generally becoming more interested in ways to become more financially independent and as thus in search of skills like trading.
Does the number of traders directly affect the volatility of the market? If it does, can we assume that trading was easier before with less traders (less volatility) than now when there are more traders, and the market more volatile?
What is more important in trading is the amounts that are used in trading. It is not actually about the numbers of traders but the capital that is involved. Just imagine 10000 people trading in the market with huge capital and at least an individual trader is trading with 100,000k , this is enought to create volatility in the market. But when the numbers are huge like 1,000,000 traders using just $100 to trade, this is not going to make a great impact and the market is not going to be as volatile compared to the former.