Where do you get your information regarding the environmental costs of manufacturing and disposal of vehicles and large appliances so that you can make this judgement?
The degree to which those two things isn't true is well outside the capability of an individual market participant. I'm at the mercy of intermediaries to expose failures in this regard.
And holding onto old products isn't much better in that regard, as I also have incomplete information on where those old parts are going, where the new ones came from, what they were made of, what hidden costs are buried in the repair business' books, etc. To say nothing of issues such as extending the life of products that rely on now-banned chemicals. Leaded paints, refrigerants like Freon, etc.