DFM
Your main reasons to your main questions are answered in today's Sunday papers. If you care to roll back the threads you will see half a dozen Pruners were trying to spell this out - but obviously couldn't because it was still sensitive (now it's out there it isn't so much anymore).
I suggest those that tried to defend the MRA4 by saying it was great and just about ready; those that had flown it or worked on it, need to take a large dose of STFU!
I am pleased someone had the b@lls to cancel it so we never have to console the likes of Tapper's Dad again.
Why was it cancelled? It was nowhere near being safe enough to fly in today's world and enough was enough.
iRaven