Yes that's how it is

When I was in the castle faze of my LEGO building childhood I'd make sure my castles always had a garderobe lol

The American model is wasteful, to fill an entire bowl. However other countries have regulations that say there can only be the minimum necessary ammount. Believe it or not, it's quite necessary to have plumbing. There's many reasons fpr why civilizations in the past were filled with diseases and one of them is because they didn't have plumbing and therefore had to carry and dispose of their waste, which increased the chance of infection. It's actually quite important to dispose of waste in a safe and practical way.

If you filled an entire bowl with shit there is no way in hell you could flush it. Anyway, low use water systems also exist in murica. Over time they are also obviously cheaper... they aren't as rare as you'd think for homes and such. Gas stations? Yeah that better have a power flush.