Most of the components of crude oil does not evaporate. Some of the lighters components will, but the medium and heavy components oxidize first and then breakdown into simpler components, similar to combustion but not as fast.
But that says nothing to the volume of oil that would have to be in the earth to make that claim true.
The Facts - the core of the earth converts carbon, oxygen (etc) via nuclear reaction to produce oil (abiotic as well as anabiotic) in (Pardon the exaggeration) GIGANTIC quanties that there is no way possible to calculate just how much is actually produced.
Most of your statements are quite true but do not underestimate the volume and workings of the mass of the earth of which we live on only a very thin crust.