“The success rate for day traders is estimated to be around only 10%,
so … 90% are losing money.” Cory Michael at Vantage Point Trading is
even more pessimistic (or realistic) when he says, “Only 1% of [day]
traders really make money.”
From Forbes (July 16, 2017).
An average 10% annual return on investment over the course of several years would be doing very well for day trading, which has to justify both large brokerage fees that accumulate on a per transaction basis, and an immense amount of time involved by someone who, to be successful, really needs to work more than 40 hours a week (trading during hours when the market is open and researching when it is not) and to have a skill set sufficient to obtain employment at $50,000-$70,000 a year or so, in a financial, economics, or management career.
So, if you have $500,000-$700,000 to invest, work 50-60 hours a week, and are extremely knowledgable and skilled, you might break even relative to the straight job. Except that pretty much anyone can passively invest and generate 4-5% per year to live on without depleting principal in the long run, which someone working a straight job could do.
So, you really need something like $1,000,000 to $1,400,000 to invest, working 50-60 hours a week, with a very high level of knowledge and skill that could get you a job paying $50,000-$70,000 in a private sector salaried job to even consider it, and even then, the risk involved in day trading is profoundly greater than the risk involved in a salaried finance job, so you really need to have more than that to invest to make it worthwhile.
If you are an MBA who used to work in a brokerage or investment bank with several million to invest and you are willing to work long hours with some funds devoted to research assistants, day trading can make sense for you. But even then, there are lots of other finance strategies, like being an angel investor or starting your own business (ideally together with other investors), that are much more likely to bring much larger returns.
If not, some people will be successful through dumb luck, but you are more likely to get ahead counting cards at blackjack in a casino or buying lottery tickets, than you are to make money in day trading. It can happen, but it very rarely does.
Most day traders don't have nearly that much money to invest, and not nearly that much expertise, which is why they overwhelmingly fail.