I think a big part of baseball's charm is it's long long history. The team in Detroit has been here for around a hundred or more years, and has only had two stadiums in that time. It is a fandom that families can pass along from generation to generation. Stories about the old horse trough urinals at the old stadium (I knew a guy who is a pharmacist and always took a medication to turn his pee bright red before he went to ball games to get plenty of room at the urinals
), seeing great players of the past, and stories about the strange things that have happened over the decades (and lots of truly strange things have happened to the Tigers over the years - go to youtube and search for Disco Demolition Night to see one of the weirdest from my childhood).
In my case, my parents moved to the Detroit area from the South in the 1950's to find work, so my children are only third generation fans. But I know plenty of people who are fourth, fifth, sixth, or much longer generation fans, with family legends centered around the team that go back for nearly that century.
The same is true for ice hockey in this area - the fandom and legends are passed on from generation to generation to generation.
In addition, with these two sports you have the long history of statistics (baseball in particular is a statistic driven sport) so you can try to compare the feats of great athletes from generations past with current athletes. One of the reasons so many people are so very upset by the steroids scandal in baseball is that major records that had been held in some cases for decades (like the single season home run record that had been held since the early 1960's by Roger Marris) were broken by people doing performance enhancement drugs. So records that had been fairly set by players consuming nothing more sinister than beer and hot dogs from the past have suddenly been smashed by cheaters fueled by winstrol and human growth hormone.