Funny how Jorge talks about "most people" like he has any kind of data.
As of last September there were less than 700'000 blockchain addresses with 0.1 BTC or more. One would think that each bitcoin believer owns at least one such address. While there are many exceptions, there are also many bitcoiners who own two or more such addresses; so, "one million" seems to be a generous estimate for the number of bitcoin believers.
I have no source for the number of people in the world who know enough about computing to understand Satoshi's paper or any of the alternative technical explanations about bitcoin, but they must be several million. That includes any computer professional who understands what public key cryptography is supposed to do (even if he does not know the details of the algorithms). Do you dispute that number?
As for another bit of evidence, I know at several dozen such people personally, including a couple of cryptography experts; and I have still to meet one who "believes in bitcoin".
Meanwhile, I'm still waiting for a demonstration of "any kid with a laptop can double the bitcoins in circulation".
I explained how in that post; it is nothing new or complicated, it has happened a couple of times already, and is often proposed (incorrectly) as a defense of last resort against an "evil" mining majority.
The kid gets a copy of the software, makes some cosmetic change that clearly distinguishes messages of his clone from those of the original version after a certain block N, and lowers the difficulty by fiat in the clone after that block so that he can start mining on his laptop. After that block, presto, every bitcoin in existence gets a clone in the kid's chain, that can be accessed with the same keys and moved (spent, sold, etc.) independently of the original bitcoin.
Whether bitcoiners will be aware of the existence of those "kidcoins", and will choose to use and/or mine them, is only a marketing problem, not a technical one...
How are miners disincentivized from including lots of transactions? The amount of transactions has no effect on how hard a block is to solve. They are incentivized to pack the block with as many transactions with fees as they can.
A miner now earns ~7000 dollars for solving an empty block, and ~7025 dollars for packing as many transactions as will fit in it. Larger blocks take slightly longer to propagate through the network, so the miner must consider whether those 25 dollars are worth the risk of losing the race just because of that handicap.
AFAIK, right now one can see many blocks being mined which are only partially full, while many transactions are pending in the queue. Clearly, the current transaction fees are not enough of an incentive.
[ Centralization of mining ] is not a problem central to bitcoin, it is a problem we've seen arise in oil, telecommunications (phone, cable & internet), banks, etc.
Indeed, and those historical examples are a strong argument for centralization of mining being inevitable. But while centralization is bad in general, it is a fundamental problem for bitcoin, because "absence of a trusted third party or central controlling authority" was supposed to be
the goal of the project. As bitcoin gurus themselves concede, a mining company or cartel who has a comfortable majority of the hashpower can control the system, e.g. by starving miners who are not part of the cartel, freezing any account that the cartel feels like freezing, etc.. Right now, one must trust that the 4-5 largest miners will not use their power for "bad things"...
The security of the bitcoin system is supposed t come not just from the technical features of the protocol, but mainly from the incentives that are assumed to convince the majority of the players to cooperate and protect it, rather than sabotage it. That assumption is far from certain if a handful of companies has the majority of the hashpower.