The lack of crowds has been extremely disappointing in this World Cup. I am sure everyone was expecting a lot more people than this.
People are losing interest in the 50 overs formats, especially in a country like India, where everyone is crazy for T20. Another reason is the games are starting in the Afternoon when the temperature is high. By evening the stadium looks better than afternoon when crowds do come in to watch the matches.
The match between South Africa and Sri Lanka is going to be another waste of time. The way Srilankans are bowling South Africa might score more than 400 runs. It is very bad to see how Srilankan cricket has deteriorated in just a few years. They were once a team that had bowlers like Vaas and Murlitharan, now they do not have bowlers who are anything near to the legends.
I have already replied to this before. I think its cursory and false to look at this in binaries, sure people are losing interest. But could things have been improved? Absolutely.
Cheaper tickets, better marketing, skillful handling of the visa issuing situation to foreign travelers etc.