The one exception to the rule is security. Nothing less than 100 per cent secure is good enough - this is one field where the suppliers' habit of getting most of the way there isn't merely irritating, it's dangerous. It's not a perfect process, just the best there is. Developments such as XML are predicated not on firmly established standards but on the promise that standards will eventually appear. Early adopters know the risks, but they also know they have to anticipate market standards if they want to stay ahead of the game.
Security is different.
Banks can't afford to open their doors online in the hope that one day someone will invent the internet equivalent of the lock and the safe. Trading exchanges can't offer to process business transactions for their customers without also giving absolute guarantees that their networks are secure. The same holds true for any organisation handling customers' money or financial details. Security has to work first time, every time. No wonder IT vendors are not much good at it.