Agressive interoperability at the protpcol and exchange format - its why email mostly works even forcing Google to back off when they tried to change email to be rendered by their cdn (i forget the name of the offering - but was similar to what news pages were being pushed for speedup). Bad actors will always abound - like Microsoft spiking the documnt standards by pushing through ooxml when odt/odf was gaining traction. Or basically just coercing the decision makers like in Berlin(?) where they moved their offices into hte city to get them to drop Linux/Openoffice.

Re: ooxml vs odt/odf

I've heard that both have parts of the spec that are hard to implement if you don't have the software to verify.

How is it a bad thing that both major office software are now documented?

As i rmeber it ooxml backers made it intentionally harder to parse the specs than was necessary ,if it was fully open i believe the open source implementation would have been on par. As it is its subtly broken in annoying ways , and with Word being the default - its version wins out and gets to be the only acceptable submission format. If you notice most doc submissions when its not a pdf being requested will specifify MS's version.And by sheer momentum the alts get less traction.