Someone rich spending a lot of money to obtain tutoring doesn't necessarily make their score higher, and there's also diminishing returns. Someone poor who do not afford private tutoring can also receive good score due to their natural talent and/or hard work in self-teaching/practicing.
> universal SAT tutoring available to everyone in order to be more meritocratic.
and that is now called school isnt it? Everybody gets at least some minimal standard of schooling.
The fact is, meritocratic is meant to describe the opposite of nepotistic (or sometimes hereditary/aristocratic). Under a nepotistic system, no matter what you do, you cannot succeed without becoming the in-group somehow.