What happened to the forked chain?
They just hard-forked silently, to have everything ready for September, and avoid another failure, if anything would go wrong.
Also, your post is yet another proof, that most users care only about block explorers, and there are not that many node runners, or even SPV clients, because otherwise you would still see the same SHA-256 chain, as all unupgraded clients can see.
He always was saying in the past that Bitcoin's blocks needed to be smaller to 300kb, no?
If we would have proper second layers, transaction batching, and cut-through automatically enforced on protocol level, then maybe even 100 kB would be more than enough. But instead, we are still in this early stage, where each user needs several UTXOs on the first layer, so instead Bitcoin is scaling through centralized exchanges, and other custodians, just because it doesn't scale on the protocol level to billions of users.
Imagine billions of users using a chain with 4 MB per block, in the way it is used today, where each user has one or more UTXOs. It would instantly explode to gigabytes of waiting transactions. However, note that if you have the same coin, passed millions of times, then you only need to know, where it starts, and where it ends, and all in-between traffic can be kept only by interested parties; the network can only validate it, and then prune it, by keeping only the minimal information, like "who owned it previously, and who owns it now".
Also, if you have billions of users, then you no longer have one user per UTXO. You have a huge multisig on both sides instead. Then, there is one 1000-of-1000 multisig on one side, and another huge multisig on another side, and the whole transaction can take less than a kilobyte, because it has the same form, as a single user, sending coins to a single recipient. Then, a single Schnorr signature can handle thousands of users. And now you have a choice: to help making it possible in a decentralized way, or to wait for exchanges, and other third parties, to handle exactly the same thing, but in a custodial way.
Note that when Satoshi wrote about scaling in the whitepaper, he only counted 80 byte block headers. Everything else he wanted to prune in that way or another, to let the network scale.
Was he thrown out?
Is it surprising? He wrote a code, that forked from the original chain for no reason, while everyone told him months in advance, how the minority chain would behave. And later, more and more people started developing solutions, which would achieve the same or even better spam resistance, without any forks at all:
https://sambitcoin.github.io/BitcoinMonetaryNode/And now, not only he competes with altcoins, using the same mining algorithm, which he hard-forked into, but he also created an unnecessary competition, by not using SHA-256, which is why all of that hashrate he convinced to signal for BIP-110, will be now redirected into mining BTC, or
Bitcoin Purity, or other SHA-256 forks.
But well, if you believe, that miners will signal, just because you wish them to, then you have to face the consequences later, if they don't.