I don't believe Sky are showing less games than before. These are additional games.
They're actually showing a few more games but that's not the point. The idea of stopping 1 provider from having all the rights was to make it fairer on the consumer but the majority of people who were subscribing to Sky for the EPL want to watch all the EPL games possible. By selling some of the rights to Setanta we now have to subscribe to them as well if we want to watch all the games possible. Had Sky had all the rights (or BBC, ITV etc got Setanta's games) then it would have cost less so for the majority of people 1 provider is better than 2.