There was a time when scoring 300 runs was a dream for every team as 180 to 220 runs was a huge target. During that time bowlers ruled the cricket and it was not very difficult for them to get wickets. With the change of time, a lot of research has been done on wickets to make the game more attractive to people and how wickets can be made to benefit the batsmen and get runs to the batsmen. The wickets in this World Cup were not for the bowlers but the wickets in this World Cup were for the batsmen and the batsmen ruled these wickets. Even after crossing 350 plus runs we saw victory and in another match New Zealand almost got close to 400 in the second innings but still unfortunately New Zealand lost that match. Now maybe such a change is happening in the future we will see more changes and that change might come in favor of the batsmen.
Yes you are right there was a time when players did a hard performance and reached only 200 around the target but at that time all the teams had the best bowlers who took many wickets and gave the lowest score to them, like Pakistan had Shuaib Akhtar, Shahid Afridi, before them, Imran Khan, Wasim Akram, Srilanka had Malinga and in the same way other teams had also their best players. But now the cricket world is ruled by the batsman they give the highest score and also chase a huge target. A live example in the recent World Cup where Maxwell did 202 runs by himself while he was injured just imagine how a person can do such a big score with an injury. Now cricket is going towards more advanced and in the coming time, I think there will be more speed in the matches and maybe the batsman can cross the 500 targets.