Our waterways are becoming more and more polluted due to PFAS, plastics, medicines, drugs, and new chemicals made by companies that just hand over the responsibility of cleaning to plants paid for by public moneys. Detecting the different chemicals and filtering them out if getting harder and harder. Could the simple solution of heating up past a point where even PFAS/forever chemicals decomposes (400C for PFAS, 500C to be more sure about other stuff) be alright?
The part you’re studiously ignoring is plenty of people saying yes, you could do this, but that it’s wildly inefficient. You could also power a bike by getting the biggest rock you could throw, tying a rope to it, applying the brakes on your bike, throwing the rock, releasing the brakes, and then pulling on the rope until you’ve collected your rock, and repeating until you’ve reached your destination. This will always work. But as long as your bike is in earthlike conditions, there will always be easier ways to do it. This is also the case for your idea.
You’re ignoring that I’m responding to the messages that say it’s wildly inefficient by saying things can change. Nowhere am I debating it’s not inefficient. You’re arguing with a strawman you built.
If by strawman, you mean fundamental laws of physics, then yes, you’re correct. If we find ways to break basic laws of thermodynamics, then I won’t be worrying about ways to sterilize water, I’ll be worrying about how to make faster-than-light starship.