This kind of shit makes me just not want to post at all.  No it isn't an admission to anyone who can read.  All security models involve assumptions upon which they derive their strength.  The assumption for Bitcoin is that the attacker will not gain 51% of the network hashrate.  If that assumption is flawed then the model can be attacked.  Likewise any other security model will involve different assumptions possible ones which are easier for an attacker to invalidate.

You will notice the words "I believe", it isn't "I know". No alternative is going to be a magic bullet which eliminates all weaknesses and creates no new ones.   It is entirely possible that I am wrong and that there is no such alternative along those lines that would result in an overall stronger network.  Security is ALWAYS about compromise.  

Guess what I can solve the "51% attack" right now.  I will give you this model for free.  A single central authority accepts transactions, verifies them, and publishes the results in the form of a ledger and diff.  These results can be verified cryptographically by any user of the network.  Transactions can be verified within seconds, nodes don't need to maintain more than a minimal amount of historical records and an attacker that isolates a node can't lie to the node it can only block information.   No amount of computing power could allow an attacker to break that system (assuming the cryptographic primitives remain strong).  It isn't 51% proof it is 100% proof.  Of course that trades the potential for an attacker to gain the majority of the computing power for the potential for the central authority to be untrustworthy.  That tradeoff is not worth it but it does "solve" most of the major limitations of the Bitcoin protocol.   Feel free to use it.

Do you get tired of being a shill?  Don't you ever just want to think and discuss?  Why not just read the post and agree or disagree without looking for some angle to exploit?  Don't you find it tedious and small?  At one time this forum (especially this section of the forum) was a place to learn, think and explore.  Lots of healthy debate, discourse, and sometimes it got heated but it was about learning.  I guess that is dead now.  Honestly I don't give a shit anymore.  This will be my last post.

On edit: edited for clarity.