In driving school we learn to treat these painted areas “as if they were a physical barrier”. I think that’s what @aighes is referring to.
But it’s definitely not consensus to always map this constellation as 2 separate ways. The only thing that is consensus is that if 2 lanes are physically separated, then they should be mapped with 2 separate ways. Physical separation in OSM does not include paint.
The consensus doesn’t say anything about when to map 2 non-physically separated lanes as separate ways, so this is up to the mapper’s discretion. There are cases where it makes sense to map them separately, and there are cases, where it doesn’t.