While hiring college and essay counselors, one-on-one test preps, etc. is certainly one (big) way that one can substantially up one’s odds at highly selective colleges, that’s not the primary way.
The money part comes into play much, much earlier - which neighborhood your parents can afford to pay taxes in, to support well-funded local school systems, or pay for preschool, enable you to many early-age enrichment opportunities, or possibly pay for private high schools that have strong connections with college admissions reps.
The money part comes into play, whether your parents work three jobs and won’t have the ability/time to engage with you about your school work, model good study and time management habits, or even attend parent-teacher conferences, pay/take you to extracurriculars,…
What made you seemingly “smarter” by the time you take the SAT, is to a large degree a function of your financial household situation (long before you start adding the last-minute 50 - 100 points by affording intense personalized prepping.)