I don't know if an anti-trust lawsuit is adequate, but governments should ban adoption of proprietary formats entirely.
I called OOXML a boondoggle because that what it was. Microsoft's documentation of the format consisted of a several thousand pages long semi-binary dump of the files produced by Microsoft Office - which are not much more than memory dumps containing binary blobs, poured into an XML container with vague descriptions of what the data types actually were - often no more than 'as produced by Microsoft Office version x.y'. A large portion of the original OOXML files consisted of blobs of binary MS Office data, making it close to impossible to implement that version by non-Microsoft entities. When pressured Microsoft agreed that the current versions of Microsoft Office were not producing 'standard-compliant' OOXML but that this would change in newer versions. Well, the future came, the OOXML format was cleaned up and documented so as to be interoperable but Microsoft never adapted Microsoft Office to the standard, instead producing its own iteration of 'the standard'.
In short, the only reason why they every produced OOXML - the 'standard' - was to use it as a club to wield in negotiations. They never meant for it to be an actual data interchange standard, they never aimed at having third parties stand on a like footing with regard to which version of OOXML was meant to be canonical. It was, and still is, meant to be a box to tick on a compliance list for getting large contracts, not a file format standard to which their products would be tailored. Their vision is whatever is produced by the latest incarnation of Microsoft Office is 'the standard', just like before.
The real question to be answered here is why ISO went along with this charade when they already had a working file format standard in the Open Document format. They could just have said 'no' like other standards bodies did, Microsoft could have been made to implement the ODF format and the world would be a better, more interoperable place.
So indeed, Microsoft should not be allowed to use a file format of their own design when implementing their own software while selling it as if it abides by an ISO standard.
Its closest real competitor was WordPerfect, but by the time the world shifted to Windows versions of thing (ie, not DOS versions), WP's goose was cooked and the only real player in offices was Word.
It's not that way now because of inroads made by online tools / web-native things that make traditional document production less important than it used to be, but they're still the 400 pound gorilla. They're just not really a monopolistic gorilla.
Or maybe it was just a luck for MS, who knows...
> Why isn't there an anti-trust lawsuit against this artificial monopoly on office formats?
What? You want it to be illegal for Microsoft to use a file format of their own design when implementing their own software?