Nope, the poor don't get poorer under capitalism.
In a capitalist society, the rich may or may not get richer, but overall, the poor also get richer, and some poor get much richer.
No other system has proved to lift more people out of poverty than systems that embrace capitalism - all of the Marxist derived systems have failed.
Even China, a supposedly communist system of government is in effect capitalist.
There will always be people who bitch about how unfair capitalism is when most of the time its because some people are just better at getting ahead than others.
So yeah, life is unfair but capitalism is fairest to those who drag everyone else out of poverty.