If baseball and the MLB are declining, then what do you consider the NHL? Yes it's been in our face the past few weeks, but the regular season is brutally boring. I watched every second of every Rangers playoff game, but watched maybe 7/82 regular season games. If you want to take your weird vendetta to a sport, don't point it at my pastime!
On the baseball/soccer argument, I grew up playing baseball, and followed the Yanks harder than anything. I missed maybe 75-100 of their ~1200 games from 2005-2013. Now, due to college and having a life/job, I catch about 60% of their games. However, soccer is quickly catching up. I discovered it in 2010, and by 2014 I was all in. It's now 3rd place, by a large margin both ways, in which sports I follow the hardest (MLB, CBB, FIFA, NFL, NBA, etc). Still, when I try to talk sports with friends, the vast majority know baseball a helluva lot better than soccer. It is no doubt on a swift rise, but maybe not with as much celerity as you'd like.