Does the fact that the applicant does not have to receive financial aid and can pay the full cost of tuition increase his/her’s chance of getting into colleges like UC Berkeley, UCLA, or USC? ($500k+ income in family)
Yes.
All these schools are need-aware schools.
Would the increase in chance be significant?
I believe so. I know people from my school with lower scores and GPA got in because they didn’t apply for financial aid.
For the UCs and the California public school system in general, I would say so. However USoCal is need-blind and is relatively generous with merit aid as well.
suggestion for you: for future questions, title your posts more clearly.
“Does Full Pay confer advantage at USC & UC schools?” would have been very helpful.
If you are a CA resident, the cost of attendance is reasonable enough that being in the $500k+ income bracket will not confer enough advantage to compensate for inadequate grades and test scores. An ability to pay the full in-state tuition might help you in a crunch situation, but there are enough who can pay it for UCLA and UCB to pick the most qualified. I think it would make a greater difference at a campus like UCI.