> Personal tutoring for standardized tests has diminishing returns compared to just grinding...
Eh, not so sure. My son got a 32 on the ACT the first time he took it, and after 4 months of private tutoring got a 35, with 36 on math. Could he have grinded himself and got there? Possibly, but I doubt it. Having someone who knows what they're doing and holding him accountable was invaluable.