What? Since last week? Since I was a kid (in the 1950's and 1960's), baseball has seen a drop in youth participation of about 90%. In those days, EVERYBODY played baseball, knew the top MLB teams and players, etc. Nowadays, most kids play soccer (Borrrrrrrring). And some MLB baseball teams play in mostly empty stadiums. If any big sport is dying, it's baseball.
Baseball looks like it's doing pretty well over the last 60 years or so. Average attendance per game 3 time higher than it was in 1950.
Source: http://www.beyondtheboxscore.com/2014/2/10/5390172/major-league-attendance-trends-1950-2013