Why? About the only people left who use Fahrenheit are Americans - everyone else has been managing quite happily using Celsius for decades. The rest of the world should now relearn an anachronism to keep Americans happy?

But to follow your logic through, you're essentially telling people to carry two single-function wrenches, when one multi-purpose wrench would do just as well. Both wrenches achieve exactly the same result, but one can be used for purposes other than removing pedals. Why carry both?

It does rather sound like you are trying to justify your sentimental attachment to the system with which you are most familiar, rather than accepting it as an anachronism and moving on. I mean I get why that might be hard to do, and there's nothing wrong with being sentimental, but let's call it what it is.

I saw this. The designers claim it works out about 10% cheaper than conventional PCBs.

As they are here also, if the damage is caused by the lessee outside of "normal conditions of usage".

Lessors are responsible for repair/replacement of "normal wear and tear". If the vehicle fails during the lease period under conditions of normal usage, then the lessor would be expected to provide repairs or replacement. The same is true here of residential rental accomodation - periodic replacement of things like paint and carpet and repair of plumbing and electrical faults is the landlord's (lessor's) repsonsibility - they factor the cost of those things into the rental charged for the property.

Mind you, I'm not sure Australian law would even allow a 20 year lease on something like a car.

But it's a lease. If for any reason the vehicle fails during that time, the owner (not the lessee) would be obligated to provide a vehicle that does work, either by repair or replacement. I don't know how leases work in the US, but that's how they'd work in Australia.

I don't think they're expecting that people will commit to a single vehicle for 20 years, merely that they will commit to lease a vehicle for 20 years, that will likely be upgraded several times during that period. Committing to a 20 year lease means you are committing to the lease, not to the specific object being leased.