Why do I invest in Stock Market

To get rich?
Not exactly.  I want to have enough to retire and totally depend on passive income from dividend.

Is it possible?
Yes, but the capital employ could be substantial (depending on the lifestyle one aspire).  Let's say, if our living expenses is $3k a month.  We will need $36k a year.  At current environment, we can quite easily get 6% dividend a year, working backward, we will need a capital of $600k.  This is not a small sum.  Capital could be lower if you are able to find higher dividend income.  For example, for 7% dividend income, you will only need $515k to give you $36k passive income in a year.
So, can you retire once you have a capital of $500k?  Not exactly.  Things aren't so simple.  Reason is inflation.  If we spend away our dividend on day to day living, and capital remain at $500k. A few years down the road, assuming dividend stays the same, living cost would possibly go up.  That leaves us with insufficient passive income to meet the increase cost of living.  Then we will have to go back to work.

The solution?
Unfortunately, it means we will have to increase our Capital. 

Conclusion
For a sustainable retirement plan.  We will need a substantial capital of close to $1 million.  This would ensure that a portion of the dividend is being plough back as capital to cope with inflation.  So, if want to live on dividend alone, we know how much capital we have set aside for this purpose.  It's a goal achievable for some.