Single stock investing: does it work?

Most of the people who go broke in stock market follow this strategy.

1. Buy 1 stock.
2. Sell if it goes up, so that you don’t get any big winner.
3. Keep on buying if it goes down.
4. Put your entire portfolio in this company.
5. Stock keeps falling and trading stops.
6. Go broke, say stock market is gambling and never return.

Unless you are the promoter and have operational control over the company, it makes no sense to put all money on a single company from risk reward perspective.