SAN DIEGO — Sports leagues, especially Major League Baseball, are seeing declines in younger viewership. The change comes as people turn away from traditional TV viewing and toward social media, video games and streaming TV, a trend that has only grown during the COVID-19 pandemic, reports The Wall Street Journal. The New York Mets’ new owner is attempting to reverse the trend by doing a marketing overhaul with ideas that include updating technology at the ballpark, creating sponsorships that grow its brand on social media and building its “cool factor.” Other leagues are trying things, too. T…