First do your homework. If you take the time and study the market some businesses will clearly survive hard times in the market. A stock trader can buy shares in these companies during the hard times and wait until the good times to sell them and make a lot of money.
The stock market is open to the public to invest in order to somehow help themselves besides the economy itself and the companies although the money coming and in and out depends on how well the investor invests in the company as well as the effort the company put the investment towards. Therefore, investing in stock varies and is difficult depending on what situation the company is in business wise. In conclusion, the stock market is reliable in some ways but can be trouble in other words.
Investing in anything whether, it is in your own company, a university, or in gasoline for your car, it is always risky. And the same goes for the stock market, let alone a rocky market. The stocks can drop and go as they please, so you should know the risks before you look at the rewards.
The stock market is simply a form of gambling. Before 2008, many "experts" would have encouraged you to invest in "sure things" like Goldman Sachs and banks. Obviously, these companies let many investors down. The way the financial system is set up, encourages risky behavior which leads to a lot of people losing money.
No, investing in stocks now is not reliable. Investing in the stock market at any time, even in a good economy, is never reliable. You never know when a company could take a turn for the worst. One wrong remark on a company's behalf or from CEO or President, and the buyers could turn against the company and release their stock. The stock market is always a gamble.