Without going through every post I'm not sure whether it's been mentioned so far, but other than the whole 'look like a tourist thing' there is also the cost factor.

Suit, shirt and tie, or jeans and whatever......works out a lot cheaper than kilt, sporran, belt, jacket, hose, flashes, sgian dubh, kiltpin. Even if you buy what I consider to be complete and utter tat....'the clan crest range'....it's still not cheap.

Add a change for each day or every few days and you're talking a fair bit of money.
I mentioned on another thread as well, that for many things I do not find the kilt comfortable. I am sure some will disagree. I hate wearing a kilt when driving and I don't like sitting down in it. All these damned pleats bunching up under your backside! And when driving, the sporran has to be moved to the side.

The kilt is however comfortable for so many other things, but better than trousers and a pair of boots or whatever? The jury is out on that one.