2. Mutually compatible doesn’t solve all of the time wasted having to reformat as FAT32 or NTFS or to configure and support multiple filesystems like CIFS and NFS.
3. MS calls it Office. It’s neither the same team nor the same product. The macOS versions of the product are crippled with less configurability and fewer expected features. MacOS Remote Desktop provided by Microsoft is not equivalent to RDPing from Windows 10. And why shouldn’t you have the same product available for Linux? How do you know what those users want?
4. Another option would be to collaborate.
My point is not that anyone specifically dropped the ball, but that incompatibility and some kinds of changes waste time and resources.
Healthy competition is doing the best you can do, not tripping your opponent or excluding them from the race.