Not sure I follow? In the USA, most car owners keep their used cars ~4 years of ownership. So if I'm in that category, a 5 year PPF warranty would meet my needs/requirements and be the best financial value for me, no?
You should check your metrics again. Most new car owners in the US keep it closer to 8 years.
And warranty is only part of it. It's not like the 5 year and 10 year films are necessarily the same.
With water heaters, the higher end units can be similar but with more Anode rods