Landfills really aren't that bad. modern landfills have multiple layers of lining to prevent leaking into water supplies and soil. After they are full, they are covered with earth and can become usable land. Their gases have to be managed (can be burned for electricity or processed in other ways) but overall putting trash in the ground and covering it seems alright to me. The amount of land that you actually need isn…
The point is that we may not have plastic forever. Oil is a finite resource. An easy, cheap replacement hasn't been found yet. Either we abide by reducing and reusing (where we should be focused), or we should actually recycle.
With our current exposure, it is estimated that 40-50 years worth of oil remains, although there is likely to be new locations found and an overall reduction of oil usage in the coming years.