Those stats only show half the picture and that is why the OP's analysis are completely flawed. Those teams went on because they were as good with their bowling as their batting. To assume that you can win a World Cup on the strength of your batting alone is totally baseless. Never been the case and never will be. Infact bowling is even more important than batting in winning a tournament and contrary to popular belief has assumed greater importance in a time where the game has become all about batting. The aphorism "batting wins you matches and bowling wins you tournaments" is completely true and can easily be supported by statistics.
If you had run the same query for bowling that you did for batting you would've realized that all those teams were also at the top of the table with their bowling stats
2007: Australia, SriLanka, NZ and South Africa had the best averages, SRs and picked up the most wickets.
2011: Here your analysis has some merit as the Champions had a lower average and S/R than other teams but they did take the third most wickets per match (69 in 9 matches). Also Pakistan, Sri Lanka and NZ were 2nd, 4th and 5th in bowling terms. Interestingly, of the top three scorers in the tournament, 2 were Sri Lankan while one was Indian. On the other hand Sri Lanka had no bowler in the three. Moreover, both Pakistan and New Zealand did not have a single batsman in the top ten run-scorers but Shahid Afridi, Southee and Gul were the 1st, 3rd and 8th best bowlers. England had two batsman in the top 10 and better overall S/R than both Pakistan and NZ but failed to qualify.
2015: Top four teams had the best averages and strike rate
Again these are not detailed analysis and I am not saying that bowling is more important than batting but to say that S/Rs alone can explain success is extremely simplistic if not totally incorrect.