Phew .. a lot to answer A so my reply is limited to your annual mileage/average age point as that is less contentious than the EV/ICE arguments.
2 cars, one is 25 years old & covers 5k miles pa
The other is 36 yo & rarely exceeds 1k pa
The youngest was built by engineers, not accountants or geeks.
The oldest was built by the Brits. ( ) but still more reliable than today's offerings.
Both are well maintained & I confidently expect them to have plenty of life left.
2 cars, one is 25 years old & covers 5k miles pa
The other is 36 yo & rarely exceeds 1k pa
The youngest was built by engineers, not accountants or geeks.
The oldest was built by the Brits. ( ) but still more reliable than today's offerings.
Both are well maintained & I confidently expect them to have plenty of life left.