I flatly concede that new cars are safer. Granted that, it's not really that bad to maintain an old car if you take a known good platform purchased in cash and maintain it in a low rust area (which I am). I present two examples:
I have a 1991 Chevy S10 I bought in 2011. Other than fluid changes, I have put in brakes (twice), battery, starter, and a water pump in it since that time. Total cost, maybe $300? I bought the truck for $2500 and it gets around 25mpg.
I have a 2005 Scion xB. Purchased 2019, I have put only brakes into it (cost $150ish). Cost was $2800, and it gets over 30mpg almost always.
Separate to these, I have an e-scooter I use for commuting and small errands on nice days. I think the trio makes a great combo of practical stuff mover, people mover, and "just me" mover. I find it hard to believe this trio would be anything close to the carbon output of making two new equivalent cars and burning the same amount of fuel with them.
Thoughts?