I’ve exported a couple of gedcoms. The sources end up in the comments or notes field, with all the rest of the narrative in the bio. The html coding is there, which takes a lot of work to cleanup.
Since the sources are not attached to the facts part of the profile, there is nothing else that the export process can do with them.
I use RootsMagic, and there are a number of things that come across as facts: reference numbers, alternate names, and a few others. I end up exporting the newly imported file, minus some of facts that are WikiTree specific, and re-importing the file. This lessens the clean-up a bit.