"China's Vision", I mean, come on. There seems to be some opinion leaking into the title.
An elevated rail system seemed so much easier and without the difficulties that this introduced.
But an elevated rail system required significantly more investment thus it had to be city sanctioned in a large way, rather than the minimal investments this required.
Just so it can turn. I think in this specific comparison elevated light rail would be significantly less-disruptive and cheaper too.