When the odd shaped Anglia came out as a replacement, it was ugly but went well with its OHV engine. Rust used to kill those off.
I used to try and repair car bodies in the 1970s and many 6 year old cars had gaping holes in the sills. Rust was bad here due to the salt air and drivers going through puddles on the seafront.
Many garages bought cars from inland areas to sell.
Rootes cars suffered huge rusting of the wings Minis would rust all over and floors would collapse in 7 years along with the subframe. Morris minors would have the spring shackles come up through the boot floor. BMC 1100 range would rust the trumpets under the front wings plus sills. Ford Cortinas rusted around the suspension struts.
Modern cars bodies last a lot longer but electronics kill them off when they fail and cost huge amounts to replace.
Most reliable car i have had in 40 years of new ones was a Vauxhall astra 2011 2 litre diesel with no faults at all. The last 2 Volvos had no faults so i am getting another one in December.
That Vauxhall is still running at over 160,000 miles. One journey i made was 600 miles in a day and great comfort.