The trouble with throwing money at education to try to improve it is that the things we know work are, on one side, nothing to do with the schools (home environment—what needs money are social services and shit like universal healthcare, not schools, poverty-reduction is the clearest target here) and on the other, a lot more expensive than we're willing to pay (e.g. Tutorial System, very-small class sizes, that kind of thing).
So instead of going after the things we know work—either because it's outside the scope of what a school can address, or because it's far more expensive than we're ever going to pay—what money we do spend just chases a bunch of unproven and unlikely-to-succeed garbage, basically.
Schools are like the patient who needs a heart transplant, but can only afford healing crystals.
Yep, but increasing the number of teachers 2-3x is indeed politically impossible. Guessing that'd mean like 30-60% higher spending on education (you'd also have to increase wages to attract enough qualified workers, in addition to having way more teachers on payroll, and it'd be a years-long process), which ain't happening.
So instead of going after the things we know work—either because it's outside the scope of what a school can address, or because it's far more expensive than we're ever going to pay—what money we do spend just chases a bunch of unproven and unlikely-to-succeed garbage, basically.
Schools are like the patient who needs a heart transplant, but can only afford healing crystals.