Samsung's Display division sources the ultra-thin glass found in the Galaxy Z Flip from a company in which it has a major share. However, this has not stopped rumors that the same OEM now plans to manufacture the same material by itself. The apparently paradoxical move could reduce the cost of future foldables.
https://www.notebookcheck.net/Samsung-Electronics-reportedly-plans-to-bring-glass-for-its-next-gen-foldables-in-house.459986.0.html