The team has been mediocre for 20 years. They never were in much contention for a playoff spot so, especially this late in the season, spending money on tickets and concessions for a team not making the playoffs seems like a waste of time for most non die-hard baseball fans. But with the team being a playoff caliber team for about a calendar year, the fans have more of a reason to spend their hard earned money to watch a bunch of overpaid athletes who actually have a legitimate chance of winning something.
Baltimore has had more winning seasons the past couple of years, and are currently in a playoff spot right now, and had a very sparse crowd against a hated divisional rival who brought alot of their own fans with them. How many Orioles fans do you see at the Rogers Centre when the Orioles play there???
Cleveland has always had attendance issues, which is why they had the wonderful idea of having 10 cent beer night back in the 70's which turned into riot night in the stands! This season, Cleveland has been in first place for much of the season and still don't attract a very big crowd.