Lower buyin means more will go out quicker. Most of the lower tourneys (20 or less) I find you'll lose at least half the field in the first hour. 3 hours sounds about right.

Personally I'm more apt to gamble as the tourney goes on heading toward the cash looking to build a big stack to win - as you note the ITM payoffs are pretty blah when you just sat there for 3 hours. But plenty of others here will recommend you play tight until ITM, then look to double up a couple times in a final table charge. Either way is a solid strat.