So easy to cast the first stone isn't it.. Turns out game development can be complicated and delays/cancellations can happen due to unforeseen consequences. Now, do I think Microsoft and Sony should be more careful with showing of things that might be a while away from release? Yes, but to pretend like this is a "Sony" thing is ludicrous. It isn't, like you say, not as bad for MS as it is for Sony, it is just as bad.
Quantum Break was announced on May 21 2013 and released on April 5 2016.
That's a long wait too.