i am a novice wheelbuilder but it's pretty obvious to me, if you really want to save weight, you can buy a 400 gram rim vs a 525 gram rim and save 125 grams there going with 24 spokes instead of 32 isnt going to save you nearly as much. however, you haven't really told us what kind of bike and what use this is so we are all assuming it's unloaded road cycling. if you really want durability, simply go with 32 holes in the rear and a mid weight (appx 450 gram) rim. There are so many possibilities and everytime these threads come up, one person says "I had a 4 spoke 250 gram carbon rim that lasted through the Rapture and into the afterlife" then someone else tells you "you need a tandem hub respaced to 130mm with 48 spokes"
Generally speaking more spokes means your splitting up the workload more ways. it will help mask bad wheelbuilding but not solve the problem. yes, I'm sure good wheelbuilders can build you a pretty durable low spoke count wheel, but that may come at a premium.