I beg to differ on this, my birds get plenty of water, I have no health or production issues with them that would suggest otherwise, but I guarantee you just the same, that anytime there is a 'new' open water available to them be it from me putting in a bowel/bucket, a left over puddle from an overnight rain or whatever they will swarm to it like they have not seen water in days just like they swarm the feeder every time I top it off even though they still had plenty of feed to eat in the feeder... And this doesn't only apply to those that use nipples, even when I used open waterers they did the same thing anytime a new open water source was shown to them, or even when I topped off the partially full waterers...
In addition to this it's not secret that nipples are a convenience to us not them, they would much prefer open water as a convenience to them and will almost always jump at an open water option vs nipples if given the choice...
I don't doubt that is your experience. I just know that when my nipples are working, the bulk of the birds start foraging when they come out in the morning. If the nipples are dry or non-functional, they all crowd the water. That's how I know there is a problem.