The spec for office documents was authored by Microsoft( and approved by Microsoft!). The spec is basically the docx datastructure published publicly as a standard - which makes building competing office suites even harder.
Given the situation there isn't much customers can do if Microsoft decides to hike the prices anyhow they like.
Note: Indian Government recently adopted Zoho office suite to insulate themselves from Microsoft.
But I don't think many other governments or businesses have the guts to make such move.