Let me be straightforward. Modern technology is not there to make your life better. It is there to turn your lazy ass into profit centers for someone. Here's another example. It took NASA and a modern entrepreneur to turn showers into electric, cartridge based printer like artifacts to "save the planet".
If you really really want to save water, replace your showers with a wet towel and your toilet with a waterless version. Otherwise just recognize that you're too lazy to change and take your damn shower in peace.