These modifications don't seem like difficult to do in 4 months, right ?
Making the modifications is not enough. You need to upgrade every bitcoin node in the world as well.
Not really. If you keep your old node running, you copy the the old fork, if sufficient miners go with the old fork to still make some blocks. If you download the new node, you copy the new fork.
And lose bitcoin. How well do you think that will be welcomed by the greater community, and how much would you trust a currency whish did that?
If it was simple to change the hard economic consensus parameters, like block size, inflation rate, time between blocks, POW algorithm etc, it would have happened several times already. It doesn't, because people want bitcoin to be a secure store of value.
But in all of this, you don't even need to run a node. You can just connect your light wallet to one of the miner pool nodes.
Yeah, or just use PayPal if you want to trust a thrid party. Actually I think PayPal is more trustworthy than the miners. That's why I chose to run my own nodes.
Segwit as it is with 4 MB blocks can be deployed in two weeks, however. There are still thousands of nodes not supporting segwit, but it doesn't matter. Those will continue to work just fine, since it is a soft fork.
Of course it matters. That would be nodes that cannot understand segwit transactions. Yes, they wouldn't refuse the block chain, but they cannot understand it. It would see funny transactions, but accepted as "anyone can spend". If I'd pay a user with a segwit transaction, and his light wallet connects to such an old node, he would not see my transaction arrive. The user of the old node himself wouldn't understand my transaction if I were to have segwit coins and wanted to pay him. So this would be a crippled node in any case.
This won't be a problem, since old nodes don't generate segwit addresses. You can pay him with your segwit coins, and it is secure. The old node will accept the transactions and see the confirmations come as normal. (Unconfirmed transactions are insecure, of course. Unconfirmed transactions have never been secure, no matter how the transaction is created.)
The thing is that segwit is a radical modification of how bitcoin functions. I'm not saying it is bad (I think it contains some very good ideas). But it is a radically different way of doing many things. Essentially, the legacy bitcoin and the segwit bitcoin are two entirely different things. A clean hard fork is much more adequate for this.
You may argue that segwit is a cleaner way of doing things, but there is no need to hard fork for it. In fact it will be very stupid to hard fork for a simple change like that. P2SH was a much more intrusive change, and it was done by a simple flag day activation.
And a clean hard fork would also allow people to "not be tied to backward compatibility". Many crypto currencies have such a policy. There's a lot of clumsiness in the requirement of a soft fork that disappears with a hard fork. For a radical modification like this one, a hard fork is much cleaner.
Use one of the scamcoins, if you want an insecure coin which hardforks all the time. Don't think you will be able to convince all bitcoin users that would be a good idea, and then you have two coins, disruption and big losses for everyone.
The whole "leading argument" in this whole business is the irrational belief that non-mining full nodes have any decentralization value, and that old nodes with old node software are important. Both of these notions are entirely wrong, but they are the fundamental argument on which all of this dispute is based.
Don't try to tell me this is wrong. I run an exchange. A small one, about 1 million USD in monthly volume now (times two, if you count buy and sell separately). Quite often when people sell coins to me, it first takes them ages to sync their old Bitcoin QT node. There are thousands of old nodes out there, and people who run them.
My own thinking is that Core wants to push people out of the block chain, and onto the LN, because that's their toy, and they think that LN has not much to offer (probably erroneously !) apart if people are FORCED off the chain.
You should join the mailinglist and spend some time on IRC where decelopment is discussed. Perhaps it will open your eyes. This kind of conspiracy thinking is just silly. First and foremost it is wrong, because "Core" isn't developing LN. There are several implementations of LN, but none by "Core". Segwit enable a lot of other technologies as well, and some are just as compelling as LN. E.g. sidechains.
I think that *this* is the whole origin of this crazy list of arguments, that culminates in the absolute importance to the security of bitcoin of an old piece of software running on an old PC somewhere on a 56Kbit link in some basement somewhere in Africa or so, as excuse for not having to increase the legacy-transaction room on the chain.
You are the first one I've ever seen to make this excuse. Sure it isn't a straw man?
In as much as "increasing block size to 2 MB" was considered a disaster for our old PC on his 56Kbit link in that basement, visibly increasing witness data to 4 MB was not going to be a problem, because somehow, these witness data were not essential to the security of bitcoin, (you could accept that *someone* *somewhere* had checked them, right ?). One needed an army of full nodes that were constantly checking the single available chain out there in all of its details (was the argument), but suddenly, that wasn't needed any more for the witness data.
Going from 1 MB to 2 MB was going to kill all full nodes, but going from 1 MB to 4 MB of witness data wasn't a problem.
I don't think you understand how a blockchain works. You can't go from 1 to 2 MB of block data, because that would make bitcoin split into two blockchains. While 4 MB is a stretch as well, there has been a lot of research done on that subject. It suggests that 4 MB is mostly safe, while larger blocks will not be. The problems are somewhat relieved by the facts that it will be much faster to validate a segwit block, and there are incentives in place to stop the UTXO set growth.