Well, no, since that would be 150% of the maximum score.
You can buy your way to the maximum score, and people have been doing it, but test prep won't get you there. (As you note, prep is worth nearly nothing in terms of score gains.) You need advance access to the answers, or a substitute to take the test for you, or something along those lines.
Sure, yes, maybe bribery or fraud could get you there. Have there been reported cases?
Yes, there have been various reported cases of fraud on the SAT. The most prominent two that come to mind are the recent college admissions scandal, in which strategies included both (1) having a substitute take the SAT in place of the student and (2) bribing the test proctor, and the year in which every test result from South Korea was canceled due to widespread cheating.
https://world.time.com/2013/05/10/for-the-first-time-sat-tes...