It's true for any non-native format (of some complexity) in any application. Vendor A's development team spends all their time developing, testing, bug-squashi

It's true for any non-native format (of some complexity) in any application. Vendor A's development team spends all their time developing, testing, bug-squashing, updating, etc. Format A, and developing, etc. their application, and developing the two to work together. They also have all the bug data, data from users, etc. Vendor B can't possibly keep up. They have their own application and format to develop. They lack the institutional knowledge, the data, etc. There's no way their application will correctly handle complex data in Format A nearly as reliably as Vendor A (which will have bugs itself). And in this case, Microsoft's Office team probably has far greater resources overall than LibreOffice.