You should have ended that particular sentence with the first phrase.
I can't understand what you mean.
Your statement:
Again, I don't know if the 2wp using SPV could work as defined, but if they to, SC would solve all the problems Bitcoin has today and guarantee his success in the way forward.
Side chains per se, do not solve all the problems Bitcoin has today, nor are they a guarantee of anything.
What they are is a mechanism. They may have the potential to solve problems. That will depend entirely on what people do with them. They are another tool in the tool belt. It can be used to build or destroy. The existence of this mechanism does not guarantee the success of Bitcoin. It would be nice if it did, and we could all just sit back and wait for the magic to happen.
Instead there is a new tool, a new mechanism. It may be used by all sorts of people, and groups. This is great, it is the nature of open source collaboration. However we must recognize that only some people may share common goals with you or me, and others may not. And you may not know whether any particular SC creator does or doesn't. There may be wolves in alpaca clothing.
These are the sorts of things that I (and presumably CypherDoc and others) consider with caution. What makes this even more of a concern is when we see these posts that essentially say "there is nothing to worry about", "this fixes everything" or "the details of the cryptography don't matter".
Those sort of statements are either (a) just misunderstood word choices (and something else was meant by the author), or (b) maybe the author is simply misguided or exuberant , or (c) perhaps they may be malicious attempts to misguide others.
If it is (a) it tends to get more clear with some attention. If (b) it is worrisome that there are going to be coming disappointments when the hoped for effects don't materialize, and (c) is just expected and is dealt with in much the same way as (a).
What you wrote here below is sensible. We may disagree on some matters of preference, but I like that you say what side chains "can" do rather than what they "will" do. It is important to understand that they can be used and also can be abused. I think Cypherdoc is understanding the function and capabilities pretty well. I also think his caution is reasonable. Some SC may be great and solve some problems...And I think that there will be some SC that end up costing some people a LOT of their hard earned bitcoin due to fraud, misrepresentation, and blind trust. So when I see folks saying "everything is great, Side Chains are here to save us" type stuff, all the red flags go up.
I try to use high-level reasoning, for example giving for granted that making "trustless 2wp" is possible (we can't be completely sure, for now).
So, looking at the cryptomoney ecosystem I see that Bitcoin has a clear advantage to any other coin, mainly due to network effect and infrastructure built around it, and that's good.
But there are a lot of new coins coming out, and apart from some stupid copycats (most of them), some innovation is being done in the field.
I don't want to have 10 or even only 3 different coins which share the market (and hence bitcoin capitalisation and liquidity), each one filling some gap that bitcoin can't cover (or that it does badly), I would prefer Bitcoin to be "the perfect money".
Now, we know we need to be very, very conservative on the changes to the core protocol because the possibility of breakage, even when minuscule, can cause enormous problems, so we need to research and thoroughly test new ideas before they can be imported in Bitcoin.
Also, almost everyone agrees on the fact that Bitcoin development is too centralized, with a few actors having much greater role of any others in pushing some set of changes.
So, the only way left are lobbying the developers (and we don't want that), or creating completely new altcoins that has to compete with Bitcoin and anyway take liquidity and market cap from it.
Also, even if remote, there is the risk that one of these altcoin, if backed by a big corp like amazon, apple, microsoft & C could really be a Bitcoin competitor in the future: Bitcoin actual market cap is tiny even compared to the size of one the big player market cap.
How to permit innovation in Bitcoin land without some small group of people could veto them for whatever reason it is?
And for innovation in Bitcoin I mean for example: better anonymity, higher TPS, better security, more decentralized mining, and certainly NOT the raising on the maximum number of existing bitcoin units and their distribution.
I think that SC can solve this problem: it maintains what is the good of bitcoin (cap on the coins, their distribution and security for who does not want to use new features) and enable permissionless innovation for everybody who want to give it a try.
If a SC which is completely better than Bitcoin under every aspect can arise, so be it: that will be a better money for everybody, and it can grow up bit by bit without disrupting bitcoin market, infrastructure and its market cap.
Alternatively, a SC which is better than Bitcoin under only some aspects and not all of them will give more value to the whole ecosystem without any drawback: only who is interested in it uses it without taking anything to any other.
I'm unable to envision a way for a SC to destroy Bitcoin, except for the case that we already knows: altcoins.
Every time I read cypherdoc on the subject I'm unable to understand the kind of threat he sees, and it seems to me simply that he is missing the point of what a 2wp gives us.
I'll continue to read the thread with interest to better understand these kind of scenarios, if any, I thank everybody for their contribution to the matter.