Could someone please let me know whether "by far" can be used comparatively. Actually, almost all dictionary examples have used it in a superlative comparison, however I'm quite sure I have heard native speakers use it in comparative structures! Is it a common mistake by native speakers in informal speech or it is something grammatically natural?
Also, it is worth mentioning that I could not find any English grammar rule acknowledging this is wrong to use it in comparative constructions.
- Superlative: It is by far the best car in the world. (Which is perhaps the most common use of the term.)
- Comparative: This restaurant is by far better than that one.
As a non-native one I cannot find anything wrong with it, but I have no clue why no dictionary has used it in comparative form?