SATs pretty well correlate with income, so the “monied elites” are not that worried about SAT - they prefer it really (check out the SAT for your basic high-tuition prep school vs. most high performing publics.) Much easier to get (most) monied kids to get a good SAT vs. a good GPA at a competitive school.
Though they help my kids, the reality is the tests are probably not neccessary for any college admissions (and certainly not worth the sturm, drang and cost.) They benefit the wealthy (who can test prep, take multiple times and have schools that "teach to the test.) are a pointless “bridge to nowhere” that take up time from kids that could be used elsewhere, are abused by some admissions (the SAT math in engineering/stem in particular is overused/abused. See CIT, UCs etc.) and are not particularly any more accurate than dozens of other metrics.
But they are a big business with lots of built-in features (NML scholarships, admits etc.)
But I doubt college admissions process would be hurt at all if you got rid of them (and I’m one of those help by stronger SATs than GPA back in the day).
In general, it’s kind of absurd to think that any school, if it’s paying attention, with all the very specfic data points it gets each year, can’t do a fairly decent job of predicting success. Top 100 admit 10-40% of 10-50K applicants and can track their grades through the next 4 years. They all have stats departments. If they wanted, they’d have very precise metrics for what says a kid will thrive.