For most urban driving (stop and go, mix of short and long trips), a gasoline engine will last longer than a diesel simplt because it will have less cylinder wall and piston ring wear caused by unburned fuel. This assumes both are properly maintained with oil changes and quality fuel.

However, for continuous high load operation or long day running like taxi cabs and over the road trucks, diesels will last longer.

At higher loads, gasoline engines will have higher cylinder and ring wear than diesels because of higher temperatures.

Start-stop short trip driving is very hard on diesels.