It depends entirely on what scope one considers for impact. Do we count maintenance roads? Total land area disturbed? Windmill foundation pads? Global co2 levels? Abandoned equipment in general? Noise levels over how much area?
What is ‘leftover’ from an abandoned well can be as simple as a buried 6” ground level plug, or as messy as an acre of abandoned equipment and a giant oil spill/hazmat area. Plus a billion tons of atmospheric co2 - which is invisible.
Oil is so widely used because it is incredibly cheap and easy to use at large scale, with minimal obviously visible consequence.
Because co2 is invisible. And as long as we don’t spill large quantities of it, it doesn’t seem to cause any visible problems.
The effect of the low density from wind, solar, etc. isn’t visible until you go to areas it is widely deployed and then do the math on how much energy they are actually producing, which is a small fraction of what would be produced if the same area was impacted to produce oil or nuclear.
What analysis do you point to that suggests fossil fuels have a smaller impact than, say, wind?