There are a number of reasons that people want to increase
the cap on wages subject to payroll taxes.
Some reasons are good, some bad, and some noise.
Supporters falsely claim that Social Security is a
regressive tax, when the system is as a whole highly progressive. It is intentionally designed to be
progressive.
They also claim that wage inequality has caused the problems
of Social Security. The data is
cherry-picked to mislead the reader. The
changes occurred mostly in the mid-80s.
I think we can all agree that wage inequality in 2016 has nothing to do
with how wages were allocated in the 1980s.
http://www.americanthinker.com/articles/2016/06/soaking_the_rich_to_pay_more_than_their_fair_share_for_social_security.html