Re: Some major flaws about Bitcoin raised in this video clip- can anyone explain?

Daniel Larimer is a nobody.
He does not know what he is talking about.
Big "conglomerates" doing the bitcoin mining does NOT effect the security of the block chain.
Lets pretend only ONE person in the world is mining bitcoins.
Big deal.
Who cares?
There is nothing that one person can do to hurt bitcoin.
Everyone else using bitcoin has the block chain.
Easily over 1000 people have the block chain downloaded. No I didn't bother to look that up, it is a safe guess.
This one remaining miner cannot change the record, or the records of future transactions.

Perhaps I am missing something, but why does anyone care if everyone STOPS mining bitcoin?
The Bitcoin QT software will still behave as a wallet and peer to peer transaction data will still be shared among everyone elses wallet, correct?

Or are miners acting as a control node, in addition to mining?

No, Bitcoin completely depends on mining to operate. A miner in control could completely destroy Bitcoin if they wanted to. if they had a chain that took more work they could release it any time and wipe out all the transactions and miner rewards during the period they mining in secret.

Please consider that the only miners who could generate a longer chain than the rest of the network would themselves need to invest nearly 3 quarters of 1 billion dollars just to have enough hardware to 'overstep consensus' that is provided from the current pools (currently - this figure will grow larger as more entrants turn on their mining hardware for the first time in efforts to mine for bitcoin). Saying that miners could destroy it if they had a longer chain is not true - they would simply have their own blocks confirmed and would receive a larger portion of block rewards (rightfully so I might add - for they too are contributing mining power to the network) If an ill-willed miner with a half billion dollars and a chip on his shoulder thinks its better to hijack and effectively freeze Bitcoin transactions - he'll be noticed quick and blacklisted by the legitimate mining traffic even quicker.

I didn't say they would destroy Bitcoin, I said they could. How much they would have to spend would depend on a number of circumstances. Most of the calculations you see are bogus because they assume the entity would buy miners from vendors. At this point a 51% attacker would develop their own chips and produce their own hardware. They could mine in secret and release the chain after a long period of time with a bunch of empty blocks and wipe out all the transactions and block rewards over that period.