For me the method used depends a bit on how far I expect to carry water. If it is more of a continuous longer ride, then I prefer my Australia method of a lot of smaller bottles. If I'm carrying for a shorter distance then my Russia method of mostly a single large bladder across the rear rack can work too.
Comments from folks who travel across Australia and other dry places make me wonder what that is like. When it comes down to it, I guess i am most likely to just scratch those places off my to do list. If I lived there I might feel differently.
Maybe I am just lucky to have water generally available fairly frequently where I tour or maybe I just choose those places because I am too lazy to haul a lot of water. But my preference is to avoid carrying much more than 24 hours worth of water at any point on any trip if at all possible. Even then when I need much water I tend to make cooking and hygiene decisions that require as little water as possible for those days.
Road touring in the US, even on coast to coast routes, it seems typical to only have a one or two short sections where much extra is needed, so I like to just scrounge extra plastic bottles for those short sections and recycle or discard them when done with that section. When I am going off road and will be away from towns multiple days, I typically choose destinations where I can filter water as I go.
As I get older I also get lazier about how much I am willing to carry whether it is on my bike or on my back backpacking. I have gotten to the point where I will go to great lengths to cache food and/or water rather than carry very much at a time. My limit has become something like 24 hours of water and for backpacking maybe 4 or 5 days of food at a time. On the bike I try to keep it to no more than a couple days of food at a time. It isn't that I can't carry more, I just enjoy being relatively unencumbered.