Oil isn't magic, you can just make it, and the reason we don't is merely that it's expensive to do that, whereas it's just there under the ground - as a fossil fuel.

But because you can just make it from ingredients everybody already has, this puts a ceiling on its actual price if you have energy independence. If you need to burn oil, you can't make oil because that's a vicious circle which would need even more oil. But so long as the only you want oil is for its other properties that's fine.

Hydrocarbons are incredibly simple, the clue is in their name, a bunch of Hydrogen (literally the most common element in the whole universe) and Carbon (also extremely common). The only reason not to make any particular hydrocarbons you need (e.g. to make JetA for a airliner) is it'd be very energy intensive and instead you can just distil some crude oil to get the hydrocarbons you want...