Figures differ on age of cars but more like 8 years I think.
The average age of road vehicles in Europe has increased since 2000. In 2014, the average age of passenger cars was 7.4 years, 8 % older than that of the average fleet in 2000. For other vehicle types, the average age was 8.4 years for vans, 8.1 years for heavy duty vehicles, 9.1 years for...
www.eea.europa.eu
Why would you want to fit a turbo engine into a Triumph Herald? You're just making stuff up now. If they made car parts more modular the engine and other parts could at least be upgraded to improve safety/emissions/consumption.
You're making some good points but they're lost in, as killer b said, you arguing with things people haven't posted. I'm off to go for a ridiculously expensive dog walk experience instead.