Educational spending per pupil has gone up in real terms, by about 2.5x over 40 years. This is already inflation adjusted so there isn't any comparison to the inflation rate. I'd say a 2.5x increase is pretty dramatic!
But anyway hasn't the GDP and accumulated wealth of the nation increased much more over that length of time? How much of that new wealth is it appropriate to spend on education?
It might be appropriate to spend a lot on education, if there were a benefit! But as you can see in the first chart, its not at all obvious that all this increased spending has had any measurable positive effect.
I find there are benefits to spending on education! What would you prefer to do with that money?