There's another unspoken truth why MS might not have felt inclined to embrace ODT. OOo is/was essentially reverse engineered MS Office. I used to get the weekly digests from OOo, it was full of discussions along the lines of -- 'it doesn't work like that Word or Excel - fix it'.
So how come its OK for Europeans to 'make use of' foreign IPR, but its not OK for Californians/Kiwis/Aussies/Saffers etc to make Beaujolais, or Parmesan cheese
BR