First of all some of these ETF's follow indexes which are updated only once an year. Thus, they might still be holding stocks which have failed to increase their dividend in the past year due to timing.
Second, you might not want to buy certain sectors which you perceive as having further downside possibility. A weak sectors which comes to mind right now is financials, which seems to have a higher than average sector-weight in the plethora of dividend ETF's like the DVY for example.
Third, these ETF's are weighted according to different formulas, which might add to or detract from performance. I myself am a firm believer in equal weighted investing, which outperforms the market by a little over large periods of time.
And fourth the dividends from these ETF's seem to be following an erratic pattern, rather than the stable and consistent growth that their individuals stock components should have been experiencing.
