Further, further reading: https://static1.squarespace.com/static/502784a984ae2d2eef45097c/t/55eea31ce4b0c46828ef673c/1441702684565/American+Football+in+Transnat

Further, further reading: https://static1.squarespace.com/static/502784a984ae2d2eef45097c/t/55eea31ce4b0c46828ef673c/1441702684565/American+Football+in+Transnational+Context+%28JGH%29.pdf https://static1.squarespace.com/static/502784a984ae2d2eef450... TL;DR: In the mid 19th century Scrums did kind of suck (the possessor did not release the ball, sending the ball backwards was controversial, and it was twenty-a-side, so it was a mass of bodies just trying to move the ball towards opposite sides). Britain Rugby eventually responded to this, but in a different way compared to Canada and the US. The US difference was largely impacted by a single college's preference for playing eleven-a-side, which opened the game up even more than the fifteen-a-side that was adopted in Britain.