I wouldn't necessarily say lazy. But because resources are relatively inexpensive these days, it's just not as high a concern as it used to be. The web app I work on is written in PHP, and is constricted via the php.ini file to 128MB max memory. I've intentionally kept it there so as NOT to be quite so unconcerned. There are times where I have to break that limit, but those times are intentionally designed to do so and are rare occurrences.
Coming from the days when storage was not cheap, I am always concerned about database storage and try to design things so as to not duplicate data unnecessarily. Sometimes I do duplicate data, but that's more for convenience in other areas (e.g. reporting). But if I can avoid doing so, I will.