Why would a purple need to go to school after age four? It's not like purple jobs are hard. Honestly purple school shouldn't even be funded after the age of two.
So, there are two ways I could answer this. One is that I could list all the ways you could be directly inconvenienced or even killed by poorly educated purples around you. There are plenty. Does your hairdresser know how long an inch is? Does your cleaner know which chemicals don’t mix? Were your trains built by someone who’d ever met a physics textbook? When you go to a store can the staff find things in the back because they have organizational skills? If you get billed .002 tap per gig of data, will your customer service representative know that that’s different from .002 centap? Does your waiter speak in standard dialect, or do they ask if you want “a splash” with your “warm-up” followed by “fruits”? Do purples behind the wheels of trucks in your city know how to steer, signal turns, and emergency break?
But maybe you’d say “that’s the businesses’ problem; they should just train their employees, and the market will solve it”.
Now, purples do more on the job training than most castes. But if in addition to “this is how to operate this machine; this is how to cook this recipe; this is your bus route”, purples had to be trained on the job in “this is how numbers work; this is common-sense safety information for everything you will handle and everything that you might naively imagine could combine with it that’s anywhere nearby; this is what all of the long words in this spec document mean; these are the laws that apply to vehicles in general for operation, parking, and maintenance; this is how to alphabetize things, now apply it to a warehouse in three dimensions…” well, then hiring would get more expensive. Businesses would spend time and money filtering for purples who’d managed to self-teach those things or put themselves for more school. They’d cling harder to their existing adequate employees - possibly by paying them more or caving more easily to union demands. They’d do without purple labor where possible, inflating purple unemployment drastically until the credit numbers could catch up; high unemployment is bad for crime rates and social service usage rates. And all this would mean that you’d pay more for basic goods and services, wait longer for help, get your tech support through machine translation from a country that wasn’t neglecting its purple children, be at greater background risk of becoming victim to a crime, and lose any budget surplus you made on this cost-cutting measure to undereducated purples claiming the dole.
Some purples don’t need four years. I do think it’s a public good to offer them, and to require three.
