that software has to behanded "down" from some centralized locaytion and thats steemit inc for now,
The Steem software is publicly hosted on github just the same as Bitcoin. Both can be fork. For now Steemit Inc are the one most knowledgeable about the code but anyone can study it. It's open source.
What you said about the fact that if something happen to the recovery partner is also true if the recovery partner is Steemit. If the person or persons controlling the Steemit account are ill prepare in case something happen to them then they might not be able to recover the account of their people. I think the recovery partner can be changed. I'm not sure. Not through steemit but through steemd. I'm pretty sure it can be changed.
If all witnesses agree to something then they don't have to conspire to make something happen, they all agree. That's what happen Steem is updated. I don't remember how many % of the top witness have to agree but the update goes through.
For some witnesses to conspire and trying to pass false transactions would be almost impossible I think because other nodes would realize what happened and then people would very soon vote those witnesses out of their place. It would also be much more complex than people realize and those people/witness would probably have to know how to recode part of the Steem code. Not realistic stuff for many reasons.
Creating Steem account almost for free is coming in the next update and if it wouldn't it would probably be an easy thing to code if Steemit Inc didn't want it but everyone else would want this feature. The thing is Steemit Inc want this feature probably more than anyone else.