Water seems simple doesn't? But it's a resource people have been fighting for for a long time, partly because we only have had easy access to .5% of the water on the planet (see quote below). Politics, religion, culture, war, natural disasters have all limited availability of clean water. In harsher climates, people often spend half the day acquiring access to water, limiting employment, health, and spending money. Many nations in the world can't afford the infrastructure necessary to supply running water. Roughly 900 million (depending on where you get your data) don't have access to it. Even so, this is certainly a higher total than 50 years ago, or 100.
This is exactly the point. something so simple as clean water has yet to become a pervasive technology due to the reasons you mentioned, yet you seem to think somehow that in the next 20 years the entire planet is going to transform into a resource rich utopia. We'll be lucky if in 20 years there are any fish left to eat.
What is changing is affordability...as seen in the UN data I've posted before, countries and people have more wealth than ever. Add to this the scale and price of the technology available to bring access to clean water has changed, and in reality it doesn't matter if the water runs, only that it's clean...
BTW, care to guess what percentage of the world had running water 3,000 years ago?
Does the percentage matter in any way? the point is that now, 3 thousand
years later, we have yet to reach 100%.