It's going how you should have thought it would.
edit: oh right, I'm not a clickbaiter! sometimes you forget. "The Line" is going VERY badly.
I'm sorry but fundamentally it doesn't make sense. The ultimate design, imho, is approaching a sphere or ellipsoid, and existing megacities already have the jump. Go to Manhattan, if you never have, and it's not the end times, and you want to experience this approximately. hah
Also, not impressed by this production team. Multiple mistakes. Misleading, at times, the social housing in Rome thing was kinda weird. Bad graphs for representing data.
But look I'm gonna ruin this one for you; The Line isn't really going to ever meaningfully happen. That's not this world! sorry (sorry again!!)
I think the bird migration chokepoint thing pisses me off the most. Is it played up? Yeah, it might be?. But I've not seen of the birds from my childhood here anymore. Scissortail. Roadrunner. But that's b/c pesticides, not a mirrorwall. I think we've even killed off the scorpions from my childhood, like on a multiple-county-wide scale. Nobody EVER talks about scorpions here anymore. And they did when I was a kid, like all the time.