Logic dictates that rooting for a losing sports team is the height of inefficiency, and yet people do it all the time. By nature, most sports teams are losers at one point or another, no one wins all the time unless they're the Boston Celtics in the 1960s. The most sensible thing to do would be to follow the team with the best record, and to switch allegiances at will as the teams' performance varied. Hence, if the Diamondbacks were doing well this year, you'd root for them, but if they fell into a slump you'd follow whichever team was having a better year. You could limit it to regional affiliation if you insisted: but still, at the end of the day, if you lived in California you could decide whether to root for the Angels, the Dodgers, the Padres, the A's or the Giants, maybe even the Diamondbacks or the Mariners. Perhaps there could be a simple rubric for deciding which team had the potential for the most profitable fan-relationship.
But the dictates of logic have nothing to do with fandom. Cubs fans have had a tough time of it, with the longest championship drought of any team in professional sports history. So, why does anyone support the Cubs? Why do people feel such illogically strong proprietary feelings towards a team that has disappointed so often? In real life, if your spouse of significant other let you down 99 times in a row, you'd probably seriously reconsider whether or not to continue to be with them. And if you bought 99 bad issues of Superman in a row, you'd probably stop buying Superman for good, right?
Brand loyalty gets people into trouble, and it's even worse in the realm of entertainment, where brand loyalty becomes conflated with identity. No one outside of the realm of stationary retail or Wall Street gives a crap whether or not Xerox outsells Canon. Maybe an extremely small percentage of the population, office managers or whatnot, have an opinion about photocopiers, but most of the rest of us could not care less as long as the damn thing works when you go to the library or Kinkos. Maybe a few more people care about Coke versus Pepsi - most people who drink soda probably have a general preference* whether, if offered the choice between the two, they will choose Pepsi or Coca-Cola, but the majority of people probably don't spend too much time thinking about brand loyalty, they just buy what they like**. If Coke stopped making Coke, they'd switch to Pepsi or RC or Shasta (where applicable). Maybe a few more people care about cars - a few people have terrific brand loyalty, especially regarding American cars. You don't see as many "I'd Rather Push A Chevy Than Drive A Ford" bumper stickers as you used to, but they're still out there. Likewise, Honda drivers like Hondas for their longevity and easy maintenance; Subaru drivers like Subarus because of their progressive corporate practices and similar ease of maintenance.
But except for an infinitesimal minority, most people don't really identify with these kinds of economic decisions in the same we they do the decisions they make regarding their entertainment intake, be it sports or TV or comics. People identify with their favorite sports teams, they identify with their favorite TV shows, and they identify with Batman. There is no more wrenching decision for any sports fan than to see their team uprooted to a new city: what do you do? Continue following "your" team when they're halfway across the country or switch allegiances? How long? Do you continue to be a Dodgers fan, and teach your children and their children to be Dodgers fans in the heart of New York long after anyone who ever played for the team's Brooklyn incarnation is long dead?
And what if Batman sucks? If you're a fan, your allegiance to the Batman franchise sidesteps reason. If you want Batman, you have to buy the Batman comics supplied by DC. Maybe you also buy the Iron Man comics, and perhaps Spawn too, but if you like Batman you probably don't acknowledge any of these as appropriate substitutes for Batman - you'd probably be just as pissed if Iron Man sucked, and just as unlikely to buy more Batman in substitution if the situation were reversed.
Given this, it takes a lot to shake this kind of brand loyalty. Look how hard Paramount had to work to erode fan loyalty to the Star Trek brand, one of the most notoriously strong brands in all of entertainment. It isn't even really brand loyalty: if you really, really like Batman - or Star Trek, or Iron Man, or the Cubs - it's not a question of identifying with the Batman brand, it goes deeper than that. It goes to the heart of your identity in small but subtle ways. If you have loyalty to Batman you've probably been loyal to Batman since you were very young, and can't imagine a world where Batman comics didn't exist, and where you didn't buy them at least occasionally.
And by that same token, the fierce loyalty to Batman translates to a strong feeling of entitlement: if you've given a large portion of your life to the character, you have a right to dictate terms, right? You get a say, I mean, other than simply choosing whether or not to by the books? That's a given, right? I mean, if you're already going to spend $3.00+ on Batman every month, you should get some say in what happens between those pages, right? Once you've committed to the purchase, and are presumably committed to the purchase for the foreseeable future, the creators and editors have an obligation to pay attention to you, right? You get a say, right?
* To this effect, I should point out that I am the only person I know who is completely agnostic about cola - I will happily drink either Pepsi or Coke (but not the diet version of either, thank you), and will usually drink Pepsi Max or Coke Zero interchangeably. That is less of a preference than most people have, I'd wager, but most peoples' loyalty to their brand of choice is probably not very deep.
** Diet Coke drinkers are the exception: those people are fanatics.