I'l happily run fairly long distances (12 mile or so) without taking a drink with me, unless it's unusually hot weather - which isn't that often. On the occasions when I've taken a drink with me, it's the smallest of the donut bottles, and I've rarely got through half the bottle.
As others have said, if you keep yourself well hydrated all of the time, you shouldn't need to be downing loads during the run itself.
Of course, people vary and I guess some sweat more than others (though I do seem to sweat bucket loads myself!), so everyone's needs are certainly different - but not 'stupid' if you don't always take drink with you.
The only time I've really found a drink invaluable is if I've swallowed a fly, on those few occasions I've been glad of having something with me, but not for hydration per se.