Thinking about how the televised instant replay was essential to taking football over the 20th century to a major American sport from a specifically college game when college was a very specific niche thing, with a valence somewhere between lacrosse and ultimate frisbee, over the 20th century

Because the “show a play consisting of 20 guys, then show it again slowed down with someone telling you where to look and why it was significant” rhythm allowed broadcasts to not only render the action legible at first look but cultivate the football audience as they went

Other 20th cen trends it hitched on:

• The expansion of state colleges after WWII and their use as a channel for federal spending in Southern states
• The growth of high schools, with more teens enrolled, consolidation into major hubs of regional identity fit to host community gatherings