If we educated all children at an early age to read, to write, to touch type, to spell, to speak, to debate, do mental maths (the usual add up, multiply (subtract, percentages etc) - then students could leave school at 14 Learning can be condensed very quickly if rhymes and repetition are used. Not memorising is laziness. Once everyone can read you can learn online or progress more learning later in life.
Students are all kept on for political reasons now to keep the out of work numbers low. We need to regain a work ethic. Teachers should not be 'baby sitters' for the disaffected unwilling students at 17/18 years of age. If at 11 to school leaving schools introduced an hour a day of sports or fun cardio work, taught home cooking, other interesting crafts, and skills and introduced whole food lunches (soup & a wholemeal roll & fruit) and then trained everyone to swim, to do lifesaving, first aid, money skills and offered practical skills such as building, decorating, electrics - all the usual house building skills then we might have a fitter, healthier and happier student population. We should not require students to have a degree to do shelf filling or picking, but a recognised English and Maths exam.