China has been trying to close their internet since after the Olympics. It isn't surprising that they would eventually succeed at it.
Access to the open Internet is becoming less and less of a necessity. "The next big thing" isn't really happening. A country like China, having developed their own industry, can safely rely on companies coming to them or developing their own alternatives. At the same time things like ddos, ransomware, money laundering, black markets, foreign influence, rumors, populism etc. is becoming more of a problem.
It's like any other technology adopted by China. They will buy or co-develop something as long as you have something to bring to the table, when you don't they will do it themselves instead.
I don't agree with the Chinese governments position nor methods, but I'm not sure their reasoning around "cyber-sovereignty" wrong.
As for how I discovered they were unblocked, I got a phone call from my Mum early in the morning after the attack (the attack happened during the Chinese night time) and went in to the office (which had the only available internet access), and one of my colleagues told me that the bbc and nytimes were no longer blocked.
Not sure how he found out they were unblocked, but he'd been there most of the night.
Then once you know one is unblocked you try them all :-)