Every sports now days is a money game any sports does not have money involved in it then no one will be interested. Cricket and in particular T20 format has recently achieved so much money and popularity globally and one of the key players is BCCI because it conducts IPL.
After adding two new teams to IPL I think the fan base of IPL has increased and that is why the revenue from media rights rose so much.
IPL was a long tournament and people didn't show much interest unless it reaches to the quarterfinal.
even in India people didn't have time to follow all the initial matches - there are so many teams in IPL on the other hand PSL has only 4 teams and it was far better than IPL
Why would anyone watch all the matches of the IPL? (Except it's related to their jobs)
How many times we watch all matches in the World Cup? Even hard core cricket fans don't follow every team's fixtures in the WC as they focus in high profile games, casual cricket fans only follow rivalry-matches only and so it's a same with the IPL.