The difference is that the altcoin is visible from the start as a clearly separated ecosystem, while in the case of an chainsplit that is not so clear. In every chain split there will be services that were available to the users of the existing chain that limit themselves to only one chain (because of ideology or practical considerations).
I don't understand that argument. After all, the original chain is still functioning.
I think here lies our misunderstanding - in my chain split scenario (the most likely if BIP148 would compete with "Barrycoin") there would be no agreement which one is the original chain. Both the BIP148 client and the "Barrycoin" client have code in it that will eventually become incompatible to unupgraded non-Segwit clients.
Well, that's a triple split then ! There is still the unmodified chain, with the protocol of today. I was thinking of the more classical scenario when there's the original chain going on without any modification, and a new chain, which forks off with a new protocol. Then it is pretty clear that the original chain is, well, the original one. In the ethereum split, ETC is the original chain. (the battle for the NAME is an entirely different issue)
Of course, if, at the moment of split, the original chain simply stops, and two NEW chains emerge, both with a different protocol from the original one, yes, then of course you get a confusion. But that can only happen if the system is *entirely* centralized, where almost all entities in the system have colluded into one camp or another one.
I was thinking of the more "decentralized" approach when there are no "agreements in meeting rooms" at any point, but that suddenly, an entity proposes a fork as individual initiative, the rest of the system not even knowing about this plan until it is announced. Then of course, the "rest of the system" cannot collude to make a different protocol modification exactly on the same date !
How would services "disappear" from the original chain ? [...] Of course, it could be that the service provider makes up his mind to CHANGE his service and not offer it any more to the original chain - but that's an active decision on his part.
If there is no agreement which chain is the "original" one, and there is a new client A (for chain A) and a new client B (for Chain B), then there will be services that will upgrade to client A and others to client B. It is an active decision in both cases, but it's not too different from a regular upgrade of the client. It isn't important if one of the chains is "hard-forking" or only "soft-forking", both are forking.
OK, in the "double split" I agree with you. My hypothesis was that the original chain wasn't even aware of the fork until it happened of course.
My fear is that a "regularly splitting" Bitcoin will become usable only for people with a technically advanced understanding of the ecosystem. Now, with all the volatility, Bitcoin is still usable as a saving/speculation vehicle for common people (a sort of "poor man's stock"). The user has to follow one price feed and can take decisions based on it. Having to follow two feeds is already far too complex for most people.
It wouldn't be any different than coinmarketcap. A fork is just a new crypto currency, with the funny property that if you were holding coins on the original chain, you also happen to hold coins on the new one, coins which you may care about, or not. You just get a holding on a new chain if you care to download the wallet. You might just as well not.
This is no different than if one would tell you that you can download, say, a litecoin wallet, and if you put your bitcoin keyfile in there, you also happen to be the proud (or not proud) owner of a certain stash of litecoin.
If you want to stick to your original coins, and not care about your holdings on a new chain, well, that's OK too.
Also in non-speculative use cases like remittances, then in a "regularly forking" scenario both parties must pay attention to the danger of a chain split all the time. That would mean, de facto, that it couldn't be used for this purpose in an independent/decentralized way by common people but only by specialized companies that hide the hassle for you. That is also a centralization risk.
I don't see what it changes. If tomorrow, I decide to launch, say, a fork of litecoin, without even most litecoin users knowing, what would that even matter ? Ok, if most users of litecoin LIKE my fork and dump their old litecoin for the one on my chain, then litecoin's market cap will fall severely and mine will rise. But hey, if those same litecoin users suddenly like bitcoin, and sell all their litecoin to buy bitcoin, the same would happen. So for the ignorant litecoin user that doesn't know of my fork, I don't see what changes. He doesn't even need to know about my fork (ok, he will have coins he will ignore, too bad). Yes, there's a volatility risk, but that always exists.