I guess you have to look at it a couple of different ways.
1)Futility
2)Profitiability
If we are talking strictly about how futile a team is,there is no way that any other team trumps the Cubs.Think about it,not a single soul that has an account here at FreeOnes,or there parents,have ever witnessed a Cubs Championship,and they haven't even been to the Series since 1945.But even through their futility,people still show up in droves to see these pathetic losers.
If we are talking about bad franchises as a business,I don't know how anyone can really say the Lions(or any NFL team for that matter).Sure the team has sucked for many years,but every home game they have a respectable attendance for a team that went 0-16 one year ago.Same thing goes for the Chief and the Raiders.
No one shows up to Marlins games,even when they win,same with the TB Rays,who only drew a crowd only when they got into the playoffs,and they had a really good team throughout the entire season.
I guess in the current day,I would have to really say the Pirates,taking both aspects into account.They just built a brand new stadium and management doesn't even try to put a good product on the field to fill it.And even though it's not a huge market,it seem like the fans there would love to be able to go to a baseball game where their team is actually good.I almost feel sorry for them.
At runner up,I guess you could throw the Nationals in there,along with the Orioles.
There are a lot of other pathetic franchises too,like the Clippers,Golden State Warriors,Phoenix Coyote,Florida Panthers,St. Louis Blues,but these are just teams that are so bad that you don't even really care.