Also allows for a smaller footprint by eliminating a major chips and support circuitry.
And as O. Frabjous-Dey says, ain't no point in having a MacBook if it is just a MacBook Pro in a plastic case.
Plus it is the entry level machine, and the machine Apple will foist off on the education market.
Making it more expensive, isn't a good idea for that marketshare since Apple is likely using a more expensive platform than Dell's education special.
If anything, Apple may slot in a cheaper machine under the MacBook rather than shoving more expensive parts into it.