They could compete evenly now, if by evenly we mean objective standards for winning the competition.
Not necessarily. The intended-case scenario for affirmative action recipients are individuals with aptitude just as high as other candidates, but with lower performance due to lower prior opportunities (lower quality education, less ability to afford tutors and SAT prep, etc.) who quickly catch up to the more advantaged students.
Even a best-case implementation of affirmative action would probably end up going to a significant number of students who turned out not to be such, but the existing-case system does turn out such students.
Related: Heuristics for Evaluating the Soundness of the Academic Mainstream, Admitting to Bias, The Ideological Turing Test