For example, a reversal: nobody would drive their cars at all if the fuel prices would be the same for 5 seconds of driving as it is for a distance of 1000 miles now.
First example: if lots of people had that free hot water, there would pretty soon be companies offering them money for the use of it. A bitcoin miner hooked up to a stirling engine under the hot tap, perhaps?
Second example: shoe materials are probably fungible for other petrochemical products. Reduced-wear elastomers might result in fewer pairs of shoes wearing out but higher demand in other markets.
If I actually had free no-holds-barred heated water, I'd run a pipe down to the local laundry and sell it at a profit. That is the rational response - the reason you don't see people doing that is because nobody offers free heated water at scale.
Your mistake here is thinking that resources have an implicit purpose (hot water => warm showers). If that were true, Jeveron's paradox would not hold. The paradox holds because once something becomes more abundant, it can be used for totally new activities.
Where Jevons Paradox has most utility is showing the futility of unilateral individual action. Don't think you are doing anything to help the environment by turning off that light switch.
https://en.wikipedia.org/wiki/Price_elasticity_of_demand#Eff...
In the real world, efficiency increases aren't perfect, and we do use something more if it's efficient, but the vast majority of the time, the efficiency increase still reduces usage. It's usually not a maximal reduction because of the redbound effect (except for some appliances), but in every recent case, overall emergy use does drop.
https://www.everycrsreport.com/files/20010730_RS20981_bebfb5...