It's not their fault whoever developed the standard decided to make it incompatible with existing software. You seem determined that Microsoft has some obligation to make it easy for everone else, but nobody owes them crap.
Why didn't Microsoft make Exchange compatible with the earlier WordPerfect Office? Because they're all proprietary, practically designed for lock-in. Standards are supposed to allow everyone to use them. Microsoft has a long-standing problem with that concept.
You seem determined that Microsoft has some obligation to make it easy for everone else
No, Microsoft has no such obligation except for certain aspects of its criminal monopoly conviction. Of course, nobody has an obligation to buy Microsoft's products (I hope).