> Wonder how all of the focus seem to happen at the same time

Because this practice was made legal very recently in most places in the US and a concomitant advertising boom has saturated the media. Before the last few years, your average American couldn't bet on sports without visiting a casino sports book in person, or having a bookie (i.e., entering into a risky relationship with organized crime). TV sports coverage now openly refers to how you can use their analysis to make bets.