The whole point of writing software is to eliminate repetitive nature of the job. So it's quite surprising that a githook that will accomplish this task is not mainstream.
Couple of years back at BigBinary there was a vigrous debate about it and we decided to not to enforce having an empty line at the end of the file. So far we have not seen any issue because of that decision.
We do not think it is worth a PR reviewer's time to comment on having a mandatory empty line at the end of the file. This slows down the whole development cycle. Reviewer will comment about it. Developer will make the changes. Reviewer will review it again. All the tests will be executed again. All that just to ensure that we have an empty line at the end of file which no one knows why we are still using it.
So let's stop worrying about empty line at the end of the file.