I've missed these, but in fairness it could be my own fault. I follow only trolltalk and some of the links provided from here. I don't even follow the commits anymore. [ ... ] I guess you are missing the forest for the trees perhaps. The idea that anyone can grab a reference implementation and do their own sidechain makes it kind of obvious to me how sidechains could solve the scaling problems and add a whole bunch more desirable niceties to the ecosystem as well.
It was one of the devs (Peter Todd maybe) who wrote on reddit that Sidechains are not a solution for scaling. For some time now, I haven't seen them claim that they are. Sidechains are still said to be ways to test all sorts of alternative ideas without endangering Bitcoin itself.
As for myself, I have read the Oct/2014 whitepaper with some care, It mentions many examples of things that COULD be Sidechains of bitcoin; but I still don't know what CANNOT be a sidechain.
One fundamental property is that each sidechain is supposed to be designed, implemented, and managed by an independent team. Therefore the bitcoin developers cannot give any assurances that the sidechain will do what it claims to do, or will follow any constraints.
According to the paper, a sidechain can even have its own tokens, not pegged to the bitcoins that were exported to it. I cannot see how the sidechains could help bitcoin scale to hundreds of millions of users -- except by being altcoins independent of bitcoin.
As for LN, I have not followed it that closely. My impression is that it is subtly different from how I envision sidechains, but very interesting technology which will be valuable to develop and experiment with if nothing else.
The LN is very different from sidechains. It executed payments by means of "bitcoin IOUs" that are guaranteed by actual bitcoins that were locked by users for a predetermined time. While sidechains are too unconstrained, the LN is too constrained.
From all that I know, it has some formidable practical problems, like requiring that users lock in advance all the bitcoins that they intend to spend for the next 6 months into bank-like entities.
I have asked about these problems directly to Adam Back, Luke Jr, and a few other developers, including Joseph Poon, one of the LN inventors. The dialogue always ends at that point.
Well, right now, if they control Blockstream, they control the future of Bitcoin...
Considering that most of the Bitcoin 'core developers' who are worth a shit are involved, that would be true with or without the Blockstream umbrella.
The fact that sidechains and Blockstream has you (Stolfi) running scared is one of the best indicators yet that the may live up to the hopes I have for them.
So you don't mind having the bitcoin network literally owned by one company, which intends to make it unusable for its original purpose and to reuse it as an internal component of their nonsensical project... It makes me very hopeful that bitcoin will collapse -- not under external attacks, as bitcoiners always feared, but from the greed and mistakes of its defenders. It will be fun to watch...