A hundred and fifty years ago, adults were incensed about child labor. Low-wage kids were taking jobs away from hard-working adults.
Sure, there was some moral outrage at seven-year olds losing fingers and being abused at work, but the economic rationale was paramount. Factory owners insisted that losing child workers would be catastrophic to their industries and fought hard to keep the kids at work--they said they couldn't afford to hire adults. It wasn't until 1918 that nationwide compulsory education was in place.
Part of the rationale to sell this major transformation to industrialists was that educated kids would actually become more compliant and productive workers. Our current system of teaching kids to sit in straight rows and obey instructions isn't a coincidence--it was an investment in our economic future. The plan: trade short-term child labor wages for longer-term productivity by giving kids a head start in doing what they're told.
Obviously US focussed, but not much doesn't/wouldn't apply to the UK education system. An interesting article.