No, they aren't motivated by that. They are motivated purely by profit. If more miners start mining, the difficulty goes up, and therefore profit goes down. So they need to keep adding more machines. The price is driving this cycle too. The current hashrate & difficulty are at their ATH levels.
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The bitcoin advocates like to pretend this is somehow about "securing the network" instead of pure greed, but it doesn't matter either way. Even if we take them at their word, the miners have to keep pouring in more and more energy or risk a 51% attack.
If you read bitcoin.pdf, the security depends on the % of miners that are honest.
In a nutshell, more energy just means that the "difficulty" goes up, i.e more hashes are required, but that's nothing to do with security.
Well, there are - think of bcrypt :) It actually fits exactly the definition of design that deliberately becomes less efficient.
Ultimately it's a matter of the perceived cost/benefit - encryption is deemed necessary, so the benefits [perceived] offset the costs, while the cryptocurrencies' benefits don't (or do, depending on the opinion).
You wouldn't criticize a government for spending millions keeping ita gold reserves safe, even though it can store them just as easily in a warehouse as it can in fort knox
Rhetorical question, BTW. There is no market mechanism that determines what is sufficient security. This should become clear if one looks at what the network is choosing to pay the miners who secure transactions.
The block reward is now 12.6% of what it originally was, and tx fees have certainly not gone up correspondingly. So is the network now undersecured? Or was it previously overpaying for security? Again, rhetorical questions - the users of the network aren't paying for security, they're paying to have their transactions processed and have no choice but to subsidize the miners with the block reward as well. As far as how much security is needed goes, the Bitcoin answer is simply "more is more."
But in the future, as the block reward dwindles, won't market forces start to price in security? I'm sceptical, personally, because the only gauge of whether or not the network is paying its miners enough is whether or not the network works. So if, in the process of finding the proper price of security, the market goes too low, attacks will be possible and the price of BTC will likely suffer as a consequence. This would make it less attractive to mine BTC and less attractive to use BTC. You can see how this could lead to a downward spiral.
Hundreds of dollars are too much for the average joe to regularly open and close lighting channels, so we might see some kind of centralisation.
The big question is if bitcoin can provide enough value as a international settlement backbone to fund the biggest pool of sha-mining hardware in the world. If an alternstive usecase for sha-miners comes up (be it blockchain related or not) that would also be a bigg security blow (but I don‘t see this on the horizon for now)
There are lots of cryptocurrencies which have infinite supply, which means that the mining rewards will keep the network running. For example Ethereum, Monero, Dogecoin and Grin. Bitcoin will rely on transaction costs, but it doesn't provide fully deterministic security as far as I know.
As for mining, it is necessary for reasons that have nothing to do with security. If you want to send a tx, you will pay a fee or perhaps hope for a kind miner to include your spend in a block. In no way are you signaling how much you think the Bitcoin network should spend on security.
It's not like Russia adds one more guard to their gold vault, the US has to keep pace or else if Russia has 51% more guards outside their vault, then by magic they can suddenly steal/double-spend gold.
Do bitcoin folks really not understand this, or are they all just pretending to be blind because they hope it will make them rich?
That's why Bitcoin/PoW is in a different category to me: It's a Red Queen's Race where all the miners are incentivized to keep wasting more and more energy (for no greater benefit) or else risk that somebody else can execute a 51% attack.
Imagine if your email host needed to keep burning more and more energy, not to send any more emails, but because if they ever backed off, somebody else could steal your email address from you.